The Stovebolt Site Forums The Shop Area Engine Shop 302 GMC in 37 Chevy truck

The 302 is ready to drop in my 37 Chevy truck,well, I still have to haul it out of the cellar and out to the barn as soon as the glacier retreats.
The GMC is about 1-1/4 inches longer as measured from the rear mounts on the clutch housing to the front mount.The actual overall length is about the same as the 261 engine the truck had,so much for the long motor business.
This is a few shots of the front mount I made, simply welded a stock mount cup to a piece of 3/8 plate steel to locate it foward.Drilled a few holes to fasten to the cross member.Then with the mount mocked in place,I drilled down using a hole saw for bolt clearance.
New mount
A few more holes

Lookin good Tony --how are the home brew intake and exhaust hedders comin?

Post a few pictures of the radiator when you get it in. I need to move mine a bit forward and I am not sure just how to go about it. Joe

when I was a teenager long ago all I did to mount a 302 domed pistons abd 3z2s was tin snip the plate in front of the radiator and mount the radiator to the front of yhe shell

Looks like yer makin' good progress Tony. I still don't get how yer just gonna waltz that thing up the cellar stairs. I don't think I could carry an SM420 from the driveway into the garage much less UP some stairs!!
-David
Oh yeah, what IS up with the intake, etc.?

When I built the truck with the 261 7 years ago, I moved the radiator foward.I relocated the radiator side brackets,enlongated the filler cap hole in the nose piece,looks like it will clear with room to spare,easy.
Buzz, I nixed the home made intake,bought a 4 bbl intake from Patrick's.But I did make the headers,didn't spend any time on finish grinding,no one see's em anyways,lol.The header isa foward dump to clear the steering box, using 3 inch single pipe and muffler.
302 lump

Don't let Joy get hurt when she carries that engine up out of the basement!

Elegant lookin exhaust collection--3" single exhaust,huh--gonna use a flowmaster? Looks like water heat to the intake--pretty spiffy lookin plumbin on that oil filtration rig.

Flowmaster? you bet,one 3 inch Delta series 40.
I dragged the complete 302 out of my cellar today,piece of cake.Pipe rollers,some planks,chains and a cum a long.Using the cum a long chained to Joy's Jeep,I winched the engine up on the planks,then backed up the Jeep ,pulled the engine out.The next part was more slippery,going the 300 feet to the barn through 6 inches of icy slush on top of soggy grass pulling the complete engine strapped to a pallet.The Jeep did it's job as always,amazing traction in those cheap Cherokees.
Here's some pics in Webshots, if ya get the whole album,scroll ,click on page 3, "Tony"s GMC engine"
[url=http://community.webshots.com/user/alltruckedup

Nice pics--some chore, it appears--looks cold. What's the deal with the degree wheel on the distributor housing and the corresponding welding--is that some secret sauce advance you got goin there?

Well thanks Joe.
Buzz,I'm checking the degrees of mechanical advance in the distributor.
Flop a degree wheel on the dist body,clamp a grips on the rotor shaft,fix a wire pointer,bend for 0 degrees.Hold the [censored] securely,rotate the grips until the avance stop is reached,this one had 15 degrees or 30 at the crank shaft plus 5 more when times at idle.I brazed up the dist cam stop,limited the total crankshaft advance to 22,set the initial timing at idle to 12-14 degrees.

Tony,
I have heard you describe this extraction method before but the pictures really tell the story! It is a very impressive and the motor looks g r e a t !

Hi Tony. Really cool lookin engine there. I am in the process of putting together a 302 my self. I am interested in some of the things you did. Like the small block valves and springs. Can you give out any specs. I would like my engine to pump out some more power over the stock set up. I am lookin into pistons fro, Patricks and maybe a cam from him too. Or Clifford. I know the real ponies are made in the head. I am considering porting and polishing to some degree, I have a great article on this subject. Also have a McGurk intake with the three singles on it and a split cast iron exhaust. I like your header system too, nice work. What ever you can tell me will be really appreciated. Thanks Rick

Tony, how did you make your headers?? lol, i'm very curious./ because it looks like you have like, a pre-made flange, and then welded the pipe yourself, or...? any insight would be great. especially for those of us who are "frugal".

thanks!

.desperado.
.sam.

OK,I'm no pro engine builder...... the head has Chevy small block V-8 valves,1.94 intake and 1.60 exhaust.They are Manley Street flow,7 bucks each.The exhaust seats were replaced,the intakes opened up slightly ,standard hot rod stuff,any decent machine shop can do the work.The springs are Crower singles with a damper, so called Z-28 springs.To get an installed spring height of 1.700,a set of Manley lower spring cups fit right in the stock valve spring recess in the head.The slightly shorter valve stems messed up the rockerarm geometry,simple fix on a GMC,just drive down the valve contact pads,weld them in the correct position.
I got a cam reground by Colt Cams in BC Canada to my own specs,they do excellent work.Delta cams in Washington can do it as can Lazer Cams in Tenn or just about any of 100's of cam grinders if you know what ya want..The typical guys who have ready ground cams for these engines,Langdon,Clifford,Howard's,base their total valve lift on a rockerarm ratio of 1.5,but actually as measured,it's 1.4. So right off the shelf, you're loosing .020-.040 total lift and some duration.
I bought header flanges on Ebay,the guy has some Chevy 235 flanges advertised at the moment.The flange port openings were too large, probably for some wildly ported engine.It was a pain in the [censored] to weld in material,better to use 235 flanges and rework them to fit. Or just get a pattern from a stock manifold fange and have a fabrication shop do a set for you.At least the flanges are 3/8 stock and cheap at around 35 bucks.I got got some 1-5/8 and 1-3/4 U bends from Summit racing,cut em up,welded it all together,a 10 inch steel cutoff saw blade on a chop saw or radial arm or table saw make it easy to do square cuts or angles.I made no effort to "tune" the individual pipes as it doesn't matter on a relatively low RPM street engine.The 4 bbl intake came from Patrick's,1/2 the bucks of Clifford,using a 390 Holley 4bbl for starters.
The oil pump pick up tube is fairly small on GMC's,a reworked larger diameter Chevy small block tube with a home made pick up looks better.
This engine wasn't cheap,I do my own assembly and design,but all the machine work,Venolia pistons,valve train,a million little this and that's has cost around 3500 bucks,ouch!Even the bearings were a fight,the only readily available mains are made in Mexico Federal Moguls,took some searching to find premium Clevite 77's.
When I started building this engine, I got a lot of bogus information from from vendors and guys who supposedly are GMC experts,like a GMC is some special magicial engine.

Thanks Tony. Good info there. Maybe I can put some of it to work on my build up. I know what you mean on the cost of these Jimmy rebuilds. It is kinda pricey. I really did not want to see another small block rod myself, so the 302 was my first choice after reading about the history of the engine. Pistons are my next purchase then a cam. Good luck with yours. See ya around the Bolt!