Inliners International Forums General Discussion Engines Hi Guys new here with a GMC 302!

Hey all,

just picked up a 17,000 mile GMC 302. Out of a Canadian Firetruck 1955( I believe the motor is a 4004(1956). Looking forward to learning about the 6 cylinders and all they are about. Just wondering on the best place to find certain parts..like a used exhaust mani a 270 generator, crank and water pump pulley(3/8") etc ...any help is appreciated! My plans are to clean it all up on a stand and plan a project for it.

There is a lot here. Try to search old threads. I don't know what you mean by a 270 generator. Must car parts stores can order water pumps with the pulley you need. Best gaskets make the best gaskets. Search eBay. Patricks in Arizona has parts just be careful there and only order what is in stock. They have cast exhaust headers.

Thanks for your help...sorry was referring to a smaller sized pulley set up but I understand I can retrofit a 7/8 pulley to fit a modern alternator...

Welcome to the forums. Based on your posting it sounds like the engine was already yanked when acquired it . . . do you have the original crank pulley? In this era both Chevy and GMC used a combination harmonic-balance-pulley. So if you have the original I would stick with it. To Beaters point one can still get 5/8 belts and retro the 5/8 generator pulley onto an alternator.

Are the exhaust and intake manifolds missing entirely?

Thank you! Yes it was out of the truck...and I will definitely try and get a new belt of the original type once I retro the pulley onto an alternator...the engine is complete and very nice except one corner of the exhaust mani flange has broken and that compromised one of the bolt holes...creating an exhaust leak. The crank / balancer is there and in great shape. Thank you for your reply.

What are you putting it in? It sounds like you are about to have some fun. 302 intake ports are larger than all GMCs except for the H-head used earlier. The 302 head has a unique combustion chamber which calls for the right pistons. The bolt hole should be east to repair. Keep us posted on your build. I have a 270 in a '53 Chevy pickup. I built the engine the first time in 1978. I could not find a 302 at the time.

Thanks Beater! I am going to learn about the motor first,..they are completely new to me..I did not know about having to change the bell to accommodate a more street friendly transmission...etc etc...I am looking for some kind of 60s COE project ...maybe a wrecker. It will be a retirement present to myself but would like to have a Manual gear mated to it with engine all clean n fixed up..then start to shop.

My 270 has the stock bell housing. I have had a few different transmissions. All of the GM trannys with the standard bolt pattern bolt to it. There is a shaft length issue with the T-5s. A COE wrecker would be a kick.

ok great ill look for a 270 bell...going to start with a home made motor cart and a tuneup etc...

Check the bolt pattern of your 302 it should be the same unless t was an automatic. In that case you'll nee a flywheel too. I'm not sure but 235-261 Chevy bell housing may fit. One for a pickup or truck will let you keep the foot starter.

Great info thanks! I've ordered all the tune up parts am looking at nickel playing the side cover and valve cover....or copper....

II like the GMC valve covers better than most of the after market ones. Besides they make a GMC look like a Chevy. I cleaned all of the sheet metal pieces of men to bare metal and finished them with steel wool, not too shiny. Then I sprayed them with Simi gloss clear. They looked great for a few tears. I'm sure there is a better coating. The engine color was cast iron color engine paint. They are great looking engines. I'm helping a friend pick up a 270 on Saturday.

does he happen to have a spare bell housing? It looks to me like the one I have is a bit large and only fit some big 5 speed they used to have in these old firetrucks? They say the 270 Bell is the way to go as it will house the original starter setup?...still learning here.

There may have been something different on the big trucks but I don't see why. I'll look around and see what I can find.

What I have read about the big truck applications for the 302 indicate that they used the 13” Brown and Lipe clutch - which demanded a bigger flywheel and bell house.

Ok, Thanks. Do you know if the Chevy bell housings will fit? I'll look tomorrow at the Northern Nevada Chapter swap meet. How would we get one to Canada?

I put a GMC 302 in a 40 Chevy coupe in the early 90's and still drive it today. I remember removing the 13" clutch, flywheel and bell housing. Used a big Chevy 6 truck bell housing instead and it fit right on to the GMC. I used a Chevy V8 11" clutch and pressure plate. Had to grind a little cast iron inside the bell housing to clear the spinning clutch plate. I used a new steel flywheel from Clifford. Had to use a very narrow throw out bearing (Corvette or Camaro) due to limited bell housing depth. The whole clutch system works well. Have used Sagnaw 4 speed and T5 with no bolt pattern or input shaft length problems. Transmissions are another story. Blew up 2 Saganaws and 2 T5s became very noisy. Should have gone with a Buffalo conversion to 7004R or 2004R automatics.

Thanks for the info Radar! I really appreciate the offer Beater. If you find one then great Id sure appreciate it. I have a place in Michigan I always go to have my packages sent. I however am in no rush at all. that being said Id not turn one away ever. I think a large cast one might be too heavy to ship but not sure. Im heading away on a trip for 2 weeks Monday and plan on diving into the 302 upon my return. I am as a matter of fact heading to Port Huron Michigan in 30 minutes to pick up a load of parts. I sure appreciate your help and efforts. Im sure after looking around that the bell will not be hard to find but I guess I should figure out which way I'm going with a transmission.

I looked at a 270 yesterday. It was a later one with the later GMC valve cover letters and a 6 bolt fly wheel. The casting number on the bell housing was 3837001. The number would be hidden if there is a transmission because the number is in an indentation on that surface. This one has angled flats on the bottom of each side for the motor mounts. So there has to be at least one more number for the older style with side mounts. Both will have the floor starter bolt holes and both will work for you and take at least an 11" clutch.

Perfect thank you for that info...looks like it was a common part. Something to hunt for.

The one on my 270 has the old style motor mount but I can not see the number. It is in a '53 chevy pickup and the GMC bolted right up in the rear. I had to build a front mount.

either mount will work I'm sure once I find a project. I really appreciate all your help. were going to try and fix the exhaust mani while I hunt for another in case it breaks again. 2 302 GMC motors have been scrapped locally in the last month or so...Ill keep an eye out and put a wanted ad up...

Hey beater, I just wanted to let you know that I found a flat/side mount bell for the engine...off one of the earlier Chevy motors. 3835201 is the part number...thanks again!

Good deal. There is a lot of stuff out there finding it is the problem. I went with a friend to pick up the 270 I mentioned above.

There is stuff for sure. Im going to start messing with the motor soon. this Bell will allow a motor stand that is 8' less wide which helps a lot. Would love to goto a swap meet for inliners sometime.