Who made that particular head? Aluminum and 45 degree intake ports. Does it have combustion chambers or just a flat surface?
I saw a red '35 Chevy coupe at a car show in Houston 10 years ago. It had a 302 with a 12 port Fisher head on it. Short stack Hilborne injector bodies using modern electronic injectors. The owner was from Pearland Texas. He said he had bought the engine from AJ Foyt's garage many years before.
Last edited by Fibonachu; 12/07/20233:40 AM. Reason: embedded images
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
Nick Arias Jr. (or his company did.) Flat surface.
They had been using 2 head bolts for a lifting chain to move the engine around. So I figured the head could use a re-torque. I had to hang around all day while the AC guys replaced the evaporator in my attic. Since I had some time, I popped the head off while I was at it to have a look inside. Updated page three with the corresponding pictures.
Last edited by Fibonachu; 12/07/20233:38 AM. Reason: Embedded images
Text below shows the connection between Nick Arias and the 12 port head. It was written by Herbert Hall and originally printed in Vol. 2, Issue 3 of the 12 Port News sometime in the early 80s.
Quote
Way back in issue #3, we left the story of Harry Warner and Wayne Manufacturing somewhat unfinished. We did cover the fact that sadly, Mr. Warner is no longer with us. However, we never went on to cover the story of what ever happened to those patterns for the Wayne GMC 12 port heads. In this installment of our continuing series we'll be taking a look at part of the story that deals with the Wayne Chevy 12 port cylinder heads, after Harry Warner. I would like to thank Mr. Nick Arias for spending the time to talk with me and to help fill out the details of this aspect of the 12 port story.
First, we need to go way back a bit and fill in a little of the history we left out in issue #3. The time is the Fall of 1952. In September of that year Nick Arias and Bob Toros returned to Southern California from the Korean War. Nick and Bob obtained the GMC engine that had formerly belonged to "Mr. GMC," Kenny Bigelow. They purchased it from Kenny's mother after he was so tragically killed at El Mirage earlier in 1952. During the Winter of 1952 and early 1953, Bob and Nick worked on that engine. From time to time, they needed parts and this brought Nick Arias and Harry Warner together, as Nick was out to visit Harry and to buy some parts. From this contact, Harry Warner offered Nick Arias a job, and after thinking it over for awhile, Nick accepted the position of General Manager of Wayne Manufacturing in the early Spring of 1953. It was at this same time that Harry Warner also offered a position to Bob Toros, who also came to work for Wayne Manufacturing that Summer. One of the first projects that demanded Nick's attention was the engine for the 1953 Indy 500 attempt. This was the engine that was used in the Jorge Daponte car, the "Wayne Manufacturing Special." (featured on the cover of Issue #3)
Nick Arias and Bob Toros both continued to work for Harry Warner for the next few years. Bob and Nick were responsible for the majority of engine and head work. Nick recalls them building some pretty famous pieces of machinery, including the first Ike Iacono engine that is so well known. When Nick and Bob first came to work for Harry Warner, Harry was still located at his house on Encinal Avenue in La Crescenta, California. They helped Harry move from there to 1023 South Broadway in Burbank in 1953, and later also helped him move to 432 South Victory Blvd in Burbank, in 1955. This was a productive time for both Wayne Manufacturing and for Nick Arias and Bob Toros. They still had Kenny Bigelow's stock head engine; Nick also had a Horning 12 port GMC. They did well on the Dry Lakes and at Bonneville, running #1 for two years in a row for the Russeta Timing Association.
In late 1955 and early 1956, Nick and Bob wanted to purchase Venolia Pistons from Frank Venolia. However, Frank was upset with Nick and Bob over some matter, so Harry Warner served as the mediator and got everyone together on the deal. It was at this time (early 1956) that all three men; Nick Arias, Bob Toros and Harry Warner, purchase Venolia Pistons from Frank Venolia. Harry Warner's participation was merely to help Bob and Nick purchase the company from a partner in it with them. Up to this time, Frank Venolia had never really had a formal business. There simply wasn't enough of a market for racing pistons and there were many established piston companies like "Jahn's" that were in the regular piston manufacturing field. As another bit of history, Frank Venolia owned a 2000 to 3000 Sq. Ft. building that was in back of his house. This building fronted on Fletcher Drive in Los Angeles. Frank rented a potion of this building out to Wayne Horning, so Wayne could have an address on a Front Street. Frank Venolia continued to use the back portion of the building for his piston business, as well as his regular machine shop trade.
At first, in early 1956, Nick and Bob rented some space at 432 So. Victory Blvd. in Burbank, from Harry Warner. They formed "Venolia Pistons" and began the start of what would become a major supplier of racing pistons to all of America.. Bob and Nick can be credited with making "Venolia Pistons" a national brand name product. Later in 1956, Nick and Bob continued the business, but moved across the street from Wayne Manufacturing to 439 South Victory Blvd., Burbank, California. At this address Bob and Nick set up another company, Toros Equipment Co. When Bob Toros moved across the street he took with him the blueprints and patterns for the Wayne Chevy 12 port cylinder head. Bob purchase these from Harry Warner, and Toros Equipment Co., continued to make the "Wayne" Chevy heads available to the racing community. Naturally, Toros Equipment Co. prominately featured, Venolia Racing Pistons, as Bob Toros continued to own Venolia and Toros after Nick Arias left to get married in 1957. Toros Equipment Co., went through some changes over the years. In 1959, Bob Toros brought in Bill Campbell and at that time, Bob and Bill formed "Tor Cam Industries." Bill Campbell stayed about 2 years and when he left, Joe Pisano came on board. At first, Joe sever mainly as the salesman. Enter Nick Arias once again. In late 1962, Nick bought back in with a full 1/3 partnership, along with Bob Toros and Joe Pisano, in what was then "Venolia Racing Pistons." All the efforts of Tor Cam Industries were merged into the one business of Venolia Racing Pistons. By that time, the market for 12 port Chevy heads had fallen off seriously, but more importantly Venolia Racing Pistons was making a major move other than the realignment of the partners. It was in 1963, that Venolia Racing Pistons first came out with forged pistons. Previously, pistons had always been cast. This a major technical breakthrough, and further established Venolia Racing Pistons on the top of the field. This 3 way partnership continued until 1969, when Nick Arias left to form "Arias Industries." At that time Bob Toros and Joe Pisano bought up Nick's 1/3 share and have continued to and currently still do, own Venolia Racing Pistons as a two way partnership.
Nearly all of our readers are familiar with Arias Industries and the racing and engineering accomplishments that Nick Arias has achieved. Arias Industries had produced such notable pieces of racing machinery, as the 8 Liter Hemi Chevy engine, which Nick built with Rudy Moeller. There was also the 8 Liter Arias Racing Engine which is still strongly involved in the racing business. Arias will soon release a 10 Liter Ni Cam V-8 engine, and Nick recently informed us that he will be sprint car racing this coming Summer (1982) with a special new V-6 Ni Cam racing engine, patterned after the 10 Liter Ni Cam model that has not yet been released. This V-6 engine will be in the 350-400 cu. in. range and have about 70 cubic inches per cylinder. This v-6 monster is only 19 inches long and we are all certain it will be the subject of much discussion, photograph and magazine articles. Nick Arias has been involved with the racing and performance scene for many years. He is now been intimately involved with so many with so many prominent racing businesses, starting with "Wayne Manufacturing," then "Venolia Pistons," then "Toros Equipment" (out of which came which came Tor Cam Industries and later the reformed Venolia Racing Pistons), then once again "Venolia Racing Pistons" and lastly and currently, "Arias Industries."
What ever happened to those patterns and blueprints for the Wayne Chevy 12 port heads? Well, Bob Toros still has them safely tucked away. As you may have noticed in the "12 Port News," Bob is considering remanufacturing those Wayne Chevy 12 Port Heads, this time in aluminum, if sufficient interest is generated. In another segment of this series we'll visit with Bob Toros and talk about those last years of production of the Wayne Chevy 12 port under "Toros Equipment Co." including the 12 port head for the 261 Chevy six as well as a report on the current remanufacturing plans.
Last edited by Peggy M; 12/06/20236:48 PM.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
It must just be the pictures. but it looks to me like valves would hit the non-dished area of the pistons at the end of the exhaust stroke/start of the intake stroke. The dished part of the piston doesn't look wide enough to provide space for the valves.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
I'll check everything when I go to set the lash. If it helps any, the pistons are 70 down in the hole.
I have a lot of faith in the guy that spec'd/built that engine. Afterall, it was what he did for a living. I miss my friend, Bill Schultz!! https://www.nhra.com/news/2022/heroes-lost
Down 70 thousandths would probably do it. I couldn't tell from the pictures.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
Bill, you called it. I started setting lash, cold at roughly 0.016 intake, 0.020 exhaust just as a starting point. Did 1I E, 2I, 3E, 4I, 5E. Rolled it 180 to get the rest and was stopped before #6 TDC. Only by about 1-3 degrees. So, I backed everything off, and rolled the crank around to make sure it wasn't some new bolt I put into the timing cover, even though I knew it wasn't. I made a crank timing trigger mount off the front timing cover and had replaced a cam cap bolt with a slightly longer one. The crank went around with no resistance (minus the rings and pistons.) So I verified the cam firing order since Bill liked having his cams ground by Donnie Johansen and those race car guys like mixing things up. He already got me with the standard firing order plug wires on the Ford 302 when the dumb thing had an H.O. cam. I think he did that on purpose just to test me!
Everything was standard firing order. So, I zero lashed cylinder 1 and rolled the crank over. The exhaust valve hit the piston. So, I backed that off and zero lashed the #3 exhaust. Same thing. So, I'm going to assume all exhaust valves are going to interfere. My thoughts are that I might need to find an 0.030 or 0.040 head gasket since the pistons are already 0.070 in the hole? That would give me something close to 0.100 exhaust valve clearance from the piston. Thoughts anyone? I'd really like to keep away from tearing into that block.
I could pull the timing cover to see if he set the cam straight up or degreed it.
I don't believe Schultz was hands on for this build, so whoever built it might have missed a spec somewhere? Things happen.
Last edited by Fibonachu; 12/07/20233:44 AM. Reason: Embedded pictures
Simply "no interference" won't be sufficient- - - -you'll need a bit of safe zone at the minimum clearance point. I like to use .060" as a minimum. Start a few degrees away from the expected minimum clearance point with a weak spring on the valve, and push the valve down with a lever until it contacts the piston. Use a dial indicator on the spring retainer to measure the travel. Turn the crankshaft 5 degrees and measure again. "Rinse and repeat!" It's not uncommon for the intake valve to outrun the piston near the top of the stroke and the closest contact possibility to happen after TDC if the cam has a pretty radical rate of lift. It might be necessary to do a little flycutting on the pistons if a thicker head gasket can't create enough clearance, or even run the cam a few degrees retarded. Advancing a cam increases low end torque- - - -retarding it helps top end HP. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I'm shooting for a minimum of .100 exhaust valve clearance. I forgot about the current headgasket thickness. I might have to get a .130 or more thick gasket. I'll start tearing into it in a few days. I have to go wire a '65 Coronet tomorrow and smog the wife's car. That'll take up most of my day.
Glad you found the interference before you hit the starter. Especially with that rare and beautiful head.
What is the cover in this picture for?
And is the little gizmo in the top of the distributor hole just to tell the electronics cylinders 153 vs. 624?
Thanks for all the pictures, although I may have to replace my keyboard because of all the drool in it.
Last edited by Fibonachu; 12/07/20233:45 AM.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
That cover is over the end of the camshaft on the timing cover. Just the way that particular cover was made. On the cackle car we used that spot to run the fuel pump. Which on a Chrysler Donovan timing cover, it uses a pretty big candlestick. The drive is a 3/8' hexagonal rod. You can see the set up right under the blower idler pully.
Gizmo is a cam position sensor (CMP.) The one I was building on top of the timing cover is crank position sensor (CKP.)
Also could be used to drive a fuel pump on a mechanical (like Hilborn) injection system.
Last edited by Peggy M; 12/07/20233:23 PM.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
That's exactly what's on the Chrysler. Donovan cover, candlestick, Hilborn fuel pump. Missing in the picture was the blower and bird catcher. Or maybe it was a smooth bug. I think Donovan made the cover big enough so that you could degree the cam in the car. Either way, on the 302, it's just a cap. I was measuring for making a bracket.
I pulled the cover and the cam is set straight up. Ordered some valve test springs and will get some numbers when they arrive.
While poking around the internet, found these little gizmos. https://www.lindytools.com/ihpc Might just be what the doctor ordered.
I wouldn't have even looked in that direction unless you had mentioned it. Once I started reading up on it, it was like it was created for my mess. So, kudos warranted and sent your way.
It's sitting on my work bench waiting for me to fix the valve to piston clearance. I'm also starting to consider their dash. Just to half the amount of sensors I have to find a place for on the block. I'm almost thinking of making the dash gauge less and having that dash swing down during operation. That might start some fun conversations wherever I go. Maybe a fuel gauge between the seats where no one can see it.
On the whole I am not a big fan of all digital gauges like that, but it is nice and compact and gives you ready access to all the info/controls you need.
Some kind of a swing-away panel would be cool, but I would be concered about stressing the wiring harness connector.
Those valve stem fly cutters are pretty cool. I don't have a particular need for them, but I still like the idea.
As long as the cable is secured properly, there shouldn't be any stress on the connector. That's my daily world anyway. Things that move and their connectors.
Okay. Let's see. Intakes are fine, exhaust is causing interference. Maybe Bill got aggressive on the exhaust cam lobes when he had it made. Minimum clearance, intake, at any position on the crank, was .060. With the exhaust rocker at .110 lash, I end up with zero clearance on the exhaust valve. My head gasket is approximately .060. Exhaust valve is 1.75" diameter. I didn't measure, but eyeballing in the intake port, there is roughly 1/8' between intake valve and cylinder. I'm assuming the exhaust would be similar. I stuck a feeler gauge between the piston and wall, and best I can tell, I have just over a 1/4" until I hit the compression ring from the top of the piston. Since this isn't a high revving engine, I'm thinking I can get away with another .080, AFTER I cut the piston .110 just to get zero lash, fudge in my hot lash of .020 (or less because of aluminum head on steel block?) So that means a total crescent shaped cut of .190 deep, leaving plenty of piston underneath. I don't think groove depth will be an issue, either.
Worst case, I kill the piston and have to replace the six. Or tag a valve and have to replace valves. But, ain't that what makes these one off special builds fun? I wonder if Bill had all this planned out already when he was building the thing. I gotta think he did, but no one will ever know! Everyone associated with building this thing have passed in the last few years.
2 new head gaskets are on order. The fly cutter also on order. Plan is to cut the .110, set zero lash and check exhaust clearance again before deciding final depth. I should be right where I started with zero clearance exhaust.
How does .080 piston to exhaust valve clearance sound for a late 50's GMC 302? More? Less?
I think I determined this block was built for an OEM GM head. Rough calculation had the static compression at well over 12:1. The lift on the exhaust valve is .610", intake .570". Running the stock GM head numbers brought the compression down to the 8's. And I think I'm safe in assuming the GM rockers aren't 1:1.75. So, after I open it up check to see what the rod length is, I think a new set of pistons and either a new cam or a regrind will be in order if I want to use the big shiny aluminum head. I do have the old cam and old rods with some Jahn's pistons attached, in case it can be reground and I need more OEM style rods. Won't know until I open it up and see what I got in there. Rabbit hole, here i come!
Without knowing the size of the depression in the top of the pistons you are using, I did a quick calculation of the static compression ratio on a 302 using a 4" flat top piston, a head gasket with a "bore" of 4.060 and a compressed thickness of 0.060", your head with no combustion chamber and a stock 4" stroke. Any oversized bore would increase the compression ratio. Adding in valve timing to compute dynamic compression ratio (see explanation here is WAY beyond my pay grade.
Here are some computed static compression ratios varying the distance "down in the hole" to the top of a flat piston.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
All things remaining the same, I'm aiming for .440" down in the hole.
The dish is roughly 32.68 cc (I added 4.16 cc for the exhaust valve relief I would have to put in, which brought the total cc to 36.84.) Stroke - 4" Bore - 4.060" (Apologies to everyone following along with the various numbers I was giving. I finally broke out my bore gauge.) Piston to deck - .070" Gasket bore 4.060" was the number I used. Gasket compressed - .060" I used 0 for the head chamber, even though the valves drop in some. Maybe offset by the spark plug divot.
That got me 12.84:1 with what I had sitting in front of me.
If I went to a .125" copper gasket, it would only get me down to 11.82:1
Redid the calculator using 118 cc head chamber, which was a number I found for a stock GM head. It brought me down to the mid 8's? I didn't write it down. So my guess was he started building this motor and acquired the Howard's head sometime after and bolted it on. I'm sure his plan was to go in and rework the block for the aluminum head, he just hadn't got to it by the time Covid started messing with him. So, with all the stuff I have, I'm shooting for some pistons close to .440" in the hole which will get me mid to upper 8's? Plus plenty of clearance for the exhaust valve chase. I haven't decided what to do about cam yet. Even though it's going to have some pretty hefty valve lift, I might try to run it first. Just for giggles.
I figured out who ground the current cam so I might give them a call next week and see if I can't get a cam card. Otherwise, I'm not sure if anyone close by has a cam doctor or similar.
I'll also need to talk to the piston company for recommendations since the combustion chamber would most likely resemble a square round cylinder. Flat top piston, flat head, a lot of flatness going on in there.
I popped the pan off last night even though I don't have it on a stand yet. Rods are 7", the exhaust valve is 1.75" and the intake is 2.125" In a few minutes, I'll run over to the shop and get the stand. I want to get a piston out and see who manufactured it and all the other neat stuff I can see inside. Maybe figure out where the oil pickup sits, how many quarts I can get in this and set the dipstick accordingly. I was also giving thought to ways of reducing rocker ratio. It can be done, but would require 12 rockers and new towers to relocate the rocker shaft.
Just curious: What lubricates the pushrod to rocker arm interface and the rocker arm to valve tip interface? Those are very pretty rockers, but how do they lube each end?
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
Pressure rail to head, head to rocker shaft. I believe the oil goes from rocker shaft to the rocker, then to a point out near the roller. The is also an oil hole on the pushrod side of the rocker. I believe it sprays at the junction of pushrod and adjuster cup.
I'll know when I prime the thing with the valve cover off.
What's the crankshaft rod journal size? The Nissan H beam connecting rods I'm using on my Frankenstein stovebolt stroker are a few thousandths under 6.5", but they've got a pretty small diameter bearing. They're rated for up to 1K horsepower, though, and they're not terribly expensive.
How about running a Chevy small block V8 4" diameter forged piston with a shorter compression height and the original connecting rods? Wrist pin sizes are easy to adapt with custom bushings in the connecting rods. There are lots of different wrist pin positions for 302, 327, and 350, all with a 4" bore and a .927" wrist pin. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I don't know what rods or piston pins Mark has, but the stock 302 piston pin is 1.0523"-1.0525" and the stock crank journal size is 2.111"-2.312". Edit: I fat fingered the crank journal size. The minimum should be 2.311", not 2.111". This will have an effect on Jerry's post below.
Last edited by Bill Hanlon; 11/12/20233:17 PM.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
Hmmmmm- - - - - -another option would be the 292 Chevy six connecting rod and a small block V8 piston. That would give a bunch of options for adjusting the piston compression height and the position of the piston in the cylinder, without having to go to exotic (e$$$pensive) custom pistons or rods. The 292 runs a 2.100" rod journal, the same .927" wrist pin as the V8, and a rod length of 6.760". That's almost 1/4" shorter rod length, and there would be several choices of piston pin to crown distance. Small block V8 hotrod parts are plentiful and inexpensive, and they're made to handle lots of horsepower. The existing pistons could have the wrist pin holes bushed down to fit the 292 rods, which have press fitted pins, if the shotrer rods could create enough valve clearance. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Right now I'm trying for the less expense of energy route of sticking with the rods that are in there with the .990" pins and just do a piston change out. I've learned elsewhere that CP Carillo (who bought out Arias) and Ross Racing Pistons still make pistons for the Bonneville guys using GMC's. There's plenty around if you know who/where to ask. I learned that when we were restoring the vintage fuel motor. You ask around and you eventually run in to the guy that has a garage full of hemi's, 6-71 blowers, the #3 Donavan block, and..... You just don't find them on the internet. (RIP Jake!) Fortunately, one of them is my friend. Who just spent yesterday trying to break a record at El Mirage in George Callaway's roadster. 149 mph for the first pass. He needed 152+ for the second pass but wasn't successful.
Picture from yesterday. Love the creative air dam.
So Monday, if I can find time, I'll get a call in to one or both of them and see what they can do for me and what little designs they have filed away in their computers. This block was built was within the last 5-7 years, so these pistons weren't made that long ago. They're just wrong for my application.
I don't know what rods or piston pins Mark has, but the stock 302 piston pin is 1.0523"-1.0525" .....
Why do I want to say that there are 2 pin sizes for the 302, .990" being one of them. Somebody told me that somewhere? The old rods with the Jahns pistons are .990" also.
Federal Mogul lists two wrist pin bushings for GMC sixes- - - - -1909Y has a 1.052" ID, and a 9849V is for a .990" pin. Some later model 302's ran the bigger pin, while 270 and smaller engines ran the small one.
Machine a set of custom diameter pin bushings from aluminum bronze and reduce the ID to .927, and you'll have a wide variety of 4' pistons with different compression heights go choose from. LOTS of engines ran a 4" bore, and the pistons don't care which block they're running in. Ford 289, 302, and 351 comes to mind, as well as a bunch of GM engines. Just make the rod bushings fit the wrist pins. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Machine a set of custom diameter pin bushings from aluminum bronze and reduce the ID to .927, and you'll have a wide variety of 4' pistons with different compression heights go choose from. Jerry
That thought crossed my mind as I was typing my response to Bill. I'll check Monday to see what those two manufacturers can do and at what cost. Might help to make a better informed decision. (Jeesh! I'm starting to talk like I'm at work!)
)