The Stovebolt Site Forums The Shop Area The HiPo Shop 336 Pontiac in a 58 GMC

Like I said...that's good news.

If the combination I have works out to be too low of a CR like you say, I just get another set of heads with smaller combustion chambers, and it looks like I have three choices for cc's. I really didn't want the round port heads, I know they're for higher RPM, just thought I was stuck with 'em to get the CR down.

I already have the bottom end, just don't have it together yet. Block, crank, rods and pistons, I'm not going to change any of that.

Thanks,
Greg

(1) A 500 CFM 2-barrel is approximately equal to a 354 CFM 4-barrel, the rating scales are DIFFERENT!

(2) If you want to keep GM parts, and yet be different, remember Pontiac had a factory dual-quad on the Super-Duty cars. You don't need to use the factory SD intake and carbs (expensive!!!); an Offy intake with early Pontiac AFB's will work great, and be much easier to work with than the tripower, especially at your altitude.

Jon.

So if it's 354 cfm why do they call it a 500?

I'm rounding up parts. Plenty of body's and I've got three good tops and just found three base plates

http://sdrv.ms/1aFKvmx

The outer carbs are not something you came by easily. The bases have stiffer throttle blades, no idle screws, and longer throttle shafts. Google Tri-power and you should find some venders selling replacement bases and parts. The end carbs must seal 100% so the center does all the work.

Joe

This link should explain:

http://www.thecarburetorshop.com/Carbshop_carbsizesandCFM.htm

And while I am posting links, I would highly suggest this one on tripower:

http://www.thecarburetorshop.com/Aftermarkettripowersetups.htm

And one more:

http://www.thecarburetorshop.com/Tripowertuning.htm

Jon.

Thanks CarbKing, good stuff.

I got my throttle plates today.

I'm going to try to get, and use all 66 Pontiac Tripower parts

these look right?

http://sdrv.ms/HG9zyz

Tri power linkage and fuel line mock up

not sure if this will be the final set up on the fuel lines...the factory lines look like a roller coaster

as far as the unknown pushrod length problem...I just bought a whole Comp Cams Kit. It included timing chain roller cam roller lifters pushrods rockers springs retainers keepers balls and nuts

I won't know if the pushrod length is right until I get the cam bearings in and the heads done

just need to find the time

http://sdrv.ms/1bbPSJS

Goob, Don't know if this might be of any help to you, but, my '55 2nd series 3100 has a Pontiac 400 with Muncie 4 speed. Runs great, loads of low end. I bought the truck with this engine in it, and the guy I got it from knew nothing about it either. Fits in nice, exhaust clears steering, small amount of dishing of firewall at left valve cover. A couple of C channel cross members were used for front engine mounts and rear tranny tailshaft mount. '56 auto car driveshaft from Muncie to stock rearend. Looks like the engine grew there! Must have some kind of mild cam, nice lope at idle. Holly manifold with Edelbrock 600cfm carb. Carb is outstanding. Good luck with your project!

That sounds like a real nice "Blue Chip Money Maker" as they used to call 'em. I think 55 is the first year it could have come stock with a V8. It would have been a Pontiac 287.

In doing the cam bearings I found the top end oils differently on the 389 block and the 455 heads.

The 389 gets top end oil from a cam bearing, thru a passage in the block and head. The 455 heads aren't cast to accept oil that way.

I turned the cam bearings, that feed the heads so the holes don't line up.

Anyone know why this won't work let me know!

http://sdrv.ms/18xB05c

Thanks,
Greg

Check the head gasket and see if the oil hole is open or closed, this might be a better way to blocking oil flow, and be sure you cam will still get oil since you turned the bearings. Cams get feed oil right from the crank, so the bottom oil hole should be aligned.

You might also be able to pound a lead plug into the oil passage to the old heads. I had forgotten the early engines feed the rocker arms through the head studs.

Hi,

I have a 59 GMC 100 w/ an original 336 V-8 in it. It has 74,321 original miles on it.

Hello neighbor, sounds like a nice truck. Any pictures?

My 336/455 project had taken a back seat for a while. I think I have all of the parts I'll need. Plan on messing with the heads this week. New valves, guides, springs, retainers, keepers and seals.

Greg

Got the heads done today. Dusted off the old balancing machine. Going to try and spin the crank this week and see how far off it is.

http://1drv.ms/1gxOwKA

plugging along... so far it looks like it's going to work. The timing cover, front motor mount looks like it's going to work. Pushrod length is fine. Cam bearings and top end oiling should work. I think those were the only unknowns.

For the 5 speed overdrive, the biggest issue was finding a small input shaft.

PICTURES http://1drv.ms/1g1rnFj

Pictures look good. I used to run the old style valve covers on my 455's. I took four of them and cut the top off two and bottoms off the other two, them welded the two tallest pieces together make them extra high to clear the rockers.

Joe

...for a while now it looked like the starter was going to be the Big Gotcha, or got me. With the ram air 4 round port heads and matching exhaust manifolds, there just isn't a starter that will work. Because of the block and bell housing combination I'm using, the starter mounts on the bell housing. I even tried a super small mini starter that can rotate 360 degrees but there just isn't enough room. Totally depressed and about to pull the motor out, we were standing around and staring at the situation. Then... wah lah ! we came up with this.


pictures http://1drv.ms/1vLpHmF

Wow! I just got my stroked Pontiac motor back from the machine shop on Friday. Today I finally received the back ordered ram air III manifolds. It was very obvious they weren't going to work dumping to the rear. Tomorrow I will be dropping my motor back in the 59.

I'm still having some problems with the roller rockers interfering with the valve covers, but i will sort that out soon. Thursday the truck goes to the exhaust shop.

Just for comparison my pontiac is a 1960 389 bored .040 over stroked with a 1/2 inch stroker to make 449 inches. The heads are the 1960 cast iron heads reworked for better breathing. The timing cover is actually 1958 gmc, and the block has been drilled for reverse flow like the 1955-1959 pontiac and gmc v8 motors. A 1957 pontiac tripower sits on top. The bellhousing is a 1955-1959 gmc v8 bellhousing with a 12 inch clutch inside. I'm hoping to be able to drive it again by labor day.

so are you going to have your exhaust manifolds dump to the front as well?

Yes. I dropped the motor in this afternoon. Unfortunately the front dump runs right into my brake line.... I think that will be an easy fix. Tomorrow the truck gets an exhaust.

Well? bigbadswingdaddy, how did the exhaust turn out?

I'm plugging along, slowly and not too surely. Here is what my 455 cubic inch 336 looks like.

http://1drv.ms/1rw7jhw

Looks great Greg! High rise tripower....I just recently added a pcv valve to my Pontiac engine, I had been running it with just breathers on the valve covers. Blew oil out on my exhaust manifolds and down on the ground. The engine runs so much better with the pcv system hooked up, way less oil consumption, idle is nice and stable, and the only thing that gets on my valve covers now, is dust!

The truck is up and running. I will have over 1000 miles on the motor before today is done. I'll try and shoot you some pics or a video.

My biggest challenge was getting the motor to run at a normal temperature. I had an aftermarket alluminum radiator that ended up being clogged. I purchased a new champion radiator and built a shroud, and temperature still would climb in traffic. I finally went ahead and installed a pusher fan in front of the radiator to help the motor cool while sitting in traffic. I am still convinced that part of that extra heat was from the rings setting in. The motor seems to be running cooler now that the rings have had a chance to seat. I have a toggle switch under the dash to turn the fan on and off. Yesterday, someone thouht I had a gear drive on the motor because they could here the fan whine.

a video doing a burn out ? !!!

New Problem... changed the brake booster, new booster is causing the brakes to drag. I wish I could shoot a burnout video, cops don't care much for that out here.

Goob,

Do you have any pictures of the motor mounts and how it ties into the frame?

I'm using the stock motor mounts. The front mount is the same one that came on the original 336. The rear motor mounts are on the bell housing.

Just about ready to start it for the first time. Got a little side tracked with restoring a set of saddle tanks.

http://1drv.ms/1uOrObd

lost my camera a few months back, sorta took the wind out of my sails for posting progress. I've got about 200 miles on the 455 so far and it's got GOBS of power. It will pull a pretty serious grade in 5th(O.D.) @ 2800rpm which is about 60mph with very little pedal. Had a couple of issues and leaks to work through but everything is 100% right now. I had the wrong throttle plate springs on the secondary carbs ( for vacuum ) which was a giant headache for tuning. Mechanical linkage takes a much stronger spring. Anyway, I'm very happy with the out come. I'll get a camera and a video soon.

Greg

455 cubes out of a 336 can be done with good results. I have about 2600 miles on it so far and it is awesome. No overheating , not too much compression, no issues at all really. The only surprise was I had to run the exhaust manifolds with the dump to the front because of no starter clearance. For a recap - I used a '59 389 block, '60 timing cover, '71 heads, '66 tri power, '59 5 speed OD trans. All bolt together stuff. On May 2nd I'm going to put it on a Dyno. Not going to spin it very hard, maybe 4,200-4,800 since I won't have that many miles on it and I'm more interested in the torque numbers than HP.

http://1drv.ms/1HiK6Hj

Greg

As you can see I ditched the bed and got a set of saddle tanks-n-fenders. Then came across a sleeper. Plan on painting it yellow with a white top...

https://1drv.ms/f/s!AtECkYGmn3SDlz0Vsnjtz7NN2xM9

that is sweet!