Inliners International Forums General Discussion Swap Meet WTB : Complete GMC 302

Wanting a quality engine to put in my truck.

Thanks ,

Anybody have a lead??

You might try asking on the HAMB .

Would you please define a quality engine? Describe its intended use and a few specs of the truck Do you have a cost in mind for the engine? David

You could also check the Stovebolt forum, I have seen several GMC's and and a lot of Stovebolt engines on there before in the "Freebie" section.

Yes , I have posted in the HAMB,STOVEBOLT , OLDGMCTRUCKS ,CHEVYTALK,and of course here. As I am a member of all. Want a rebuildable engine to put in my 1/2ton truck. I say that because am learning that these engines were "over" bored. Had a few leads but didn't pan out. Don't think I can "get away with"buying that2.5ton truck&ship it to me just for the engine.No place to store that truck where I live due to city regs...

The ones on Ebay i'm leary of being over bored

Ask Bob at Owen's Salvage. He and Neal Candy race one at Bonneville. It's a great yard that specializes in hot rod parts. Being a Texican you might get a deal. Don't pass up a good 270. You can safely bore them to 292. The rest is the same.
Owen's Salvage

THANX Beater
Forgot about Him. I bought some stuff from him for my 235 in the past.
Sent them an email

I have a pile of Studebaker V8s that have been sitting at Bob's for years. Long story, I need to go get them.

Typically, light boring cyls presents no problems. Cyl walls can be sonic tested first and the boring bar shifted slightly to compensate thin spots. What did you mean by "overbored"?
I've 2 complete 302s here. Haven't disassembled to inspect. A NOS head on shelf. David

Most all of the GMC blocks are very thick, and can be safely bored .125" over their stock bore size. I know of several 302's that have been bored .125" over for Bonneville cars and drag racing that never gave any trouble at that bore size. And as Beater mentioned, a 270 can be punched out to a 302 with no problems either, and are still thick enough for further over sizes beyond that.

Do 302 and 270 blocks have the same rough block casting dimensions around the cylinder area? (prior to machining)

No, the difference is the area around the bore and the 270 can not be bored to match what can be done with a 302. 270 and 302 blocks are taller than 228 and 248 blocks to make room for the 4" stroke. Bill Fisher recommended using the 228-248 crank in street engines with a 270 block. Just building a 248 would be good if pistons were available. He claimed the shorter stroke was smoother and lasted longer due to less piston travel.

I located an engine...

Great, Tell us about it.

It is a military 302 that I'm going to have rebuilt. Was making a list of things that I will need: oil pan , 3/8water pump, electric fuel pump (any recommendation?); not sure what else till they disassemble it. Where can I buy parts if needed?

Most of what you will need will be at any real parts store. Finding a parts person willing to look for it may be tough. Patrick's has a lot. Check the venders here at 12 Port Advertisers. I like Best Gaskets.

Thanx

Last one never came about.Back searching for a 302.ANY help would be appreciated !!

Check out these guys in Wellington, Texas. Bob runs a 302 at Bonneville and has connections. Tell him "Ol' Kurt" from Nevada sent you.

Owens Salvage

Thanks, I sent an email....

Bob didn't have one...

Sorry, I just looked back and saw that I had sent you there before. Our Inliner Chapter has some guys that run them. I'll ask at the next meeting. You could try to contact them on Facebook. There is a list of parts wanted and for sale.
Facebook

Thanks- I also posted on their facebook page.Really want to upgrade to the 302 from my 270...

I'll keep asking around. There are lots of them out there but the ones I know of are being hoarded. I know of a civilian NOS 302 in Fresno. The guy has several heads and lots of speed equipment he'll never use. You may have to wait for some old fart to kick the bucket and make nice to his widow.

will just keep working with what I have and keep dreamin of the Day...

I dropped off my mil302 at the machine shop. It was complete from valve cover to military oil pan. It has the 983 head&the pvc bypass also.
So how can I wake it up? Thinking regrind the cam; Venios pistons, unless I get Aris pistons. How much over bore can a stock one go? Can I get 9:1 compression and still drive it on the streets?
Any advice would be great

An important thing at this point is to be honest with yourself. What do you want it to do and what will you REALLY use it for. A full race motor on the street is as bigger pain than a stock motor on the strip. Sadly there isn't much new info on these old engines. Bill Fisher's book was done in the early '50s and deals little with the 302. A lot has been done with 302s since then. Small block V8s didn't even exist she the book was written so no SB valves are mentioned or the use of MOPSR rear seal. Talk to as many guys that run them as you can stand. Be sure to note what they were doing with their engines. A lopey,snorting Jimmy is cool until you get caught in traffic.

My dream 302 would be bored to clean up, maybe .040 or .060. It would have forged pistons, a mild super charger friendly cam. 1.86" intake valves and 1.60" exhaust, an old two piece cap Mallory Duel Life distributer, Fenton cast headers, and a McCulloch supercharger blowing through two split base 2 barrel carbs with the second barrels of each set up as secondaries. Dream on…….

I only talked with one guy about his 302.He drag races. Not looking to do that. Am waiting till the machinist tells me what the innards look like. Can get one run(one pass down&back)on salt; Arias pistons at .40&.60 over. Not sure if I should tell the machinist to do anything than stock headwork?.
Can tell you the oil inside was clean, on the stick.
If the inside look good then I only want to do the basics to make it a good streetable engine.I read that stock compression wasn't as good as say 9:1.? Need schooling in this area.Maybe regrinding crank/cam if needed. Once I here back from the machinist then I can contact about pistons, etc.

What electric fuel pump should I look for?

302s have huge ports and small valves. A boost in compression, bigger valves, the right cam, improved intake and exhaust will do a lot and not break the bank. The right gearing is important too.

Ok going to show my ignorance--

How do you boost the compression.What is original&whats best for street?
What do you think should be done to the 983head?Valve work explain
cam choice for street?can they(delta) just regrind?
I have a Clifford single 4barrel intake&Clifford headers.Wonder if Clifford will sell just the two carb intake by itself.Difference in his two Weber setup and two 4barrels;as am leaning towards dual carb setup.I have the stock rear(58GMCtruck) with 3speed trans w manual OD;but Patricks sells the ring&pinion setup.
Thanks 4 your patience with me...

For compression check out Patrick's pistons and see what the deck height would be. You can take about .035 from the head maybe more. You can take some from the block deck if needed to bring the pistons closer to the top. Have your machinist check the head and block to make sure this has not already been done. Shoot for 9 to 9.5 to 1.
A reground cam would be fine study the specs of after market cams and talk with the grinder.
Although not as vintage looking 4bbl carbs work great without a lot of linkage issues. Old 2X1 manifolds are not real hard to find.
You can easily use 1.86 intake valves and 1.60 exhaust valves. I think small block Chevy valves will work. You can go bigger but I don't think a street engine needs it. Find a set of the welded stamped steel rockers they are a bit stronger. I think SBC springs work but you may have to play with spring height. Have hardened exhaust seats installed. I need to find my GMC notes. It's been a while.
3.55 rear gears would work great with your OD. That's what I run with a T-5. Your BW OD will be fun. There are some BW OD threads on here GMC too if you can search them.
I just did this google search. 302 GMC build

Beater,
Patricks ring&pinion is 3.38:1 for the 58 truck

Thanks 4 the imput

That should work for you if you don't go crazy with your cam.I am right at 2,000 rpm at 60mph. You would be around 1.800 depending on tire size. Your '58 is open drive line so there are lots of options for you probably cheaper than Patrick's gear set. Mine is a Dana 44 limited slip from a '68 GMC.

Is there another source for a ring&pinion set for the 55-62 gm truck?

What ratio is the one you have? My son's '54 Stude had 4,27s and with the BW OD it would cruse at 70-75 around 3,000 rpn. The Borg Warner OD are 30%. Yours is probably 3.73 or 4.11. With the OD both of those are very useable. Here is a link to some goo OD info. OD LINK
By the way I am going to use those same 4.27 gears in my '26 Chevy roadster with a T-86 3 speed OD. Google some gear ratio/ tire size charts and factor in your OD. Your 3rd gear is 1 to 1. Your OD will reduce your rpm by about 30%.

I think it is 3.90, if I read correctly.

Great article on the OD setup.