The Stovebolt Site Forums The Shop Area Engine Shop 302 GMC six

I have found some 302 gmc motor out of some WW ll duck type trucks. there are several of these. Will the military motors work with regular chevy an gmc parts. Most of these motors run good what would they be worth.

Thanks Tony

Tony,

In general, most of the parts are different. GMC parts seem to be a little higher-priced and a little harder to find than the same parts for a Chevy truck engine.

The GMC 302 is an excellent engine that is more easily adapted into GMC trucks than into Chevrolet trucks (the GMC engines are a little longer than 216/235/261 Chevrolet engines.

Maybe others will state an opinion on the value of an unknown-condition 302 (or, any used 40-50 year old engine). Shipping cost is also a consideration when setting a value of an engine (from a buyer's perspective).

Here is a Convert to a 302 Tech Tip found elsewhere in this forum.

Tim

GMC motors are similar to the Chevy motors, but very few parts interchange. The distributor is an example of what will swap. Intake and exhaust manifolds do not swap.

As Tim says hop up parts for GMC motors are not as common and generally cost more.

I have a GMC 270, which is externally the same as a civilian 302 and like the power the motor makes. I'd love to replace it with a 302.

I should have a reply for the amount of engines .
There should be around fifteen or twenty of them.

I would not give more than $200 for a unknown engine unless I knew for shure there was no cracked head or block,
But if there was any info about past history of moter I would be pretty intresed
keep us updated on what you find out
I could take 2 at least:-)

Military 302's have no provision for a mechanical fuel pump,use an electric pump instead.That,a few un needed lumps on the engine casting,a different front pulley is the primary differences.
A stock 302 rebuild costs about same for a Chevy 261 for example,it all depends on how much work you do yourself and if you're lucky at scrounging parts.

15-20 302s??? Are these in Missouri?

They're worthless. I'll come get them if you'll buy my gas so you can get rid of them. Sounds like enough that I will have to make two trips.

Let us know when you get them. Some of us would give our first born for one.

I'd give $500 each for two good engines.

Stock, the DUKW would have had a 270. The DUKW is worth a lot of money, please don't part it out if it is salvageable.

Yes they are in Missouri. My man should be running down the info on them as we speak. When I learn something I'll let everyone know. Also where is the casting number on the block or head so you can tell for sure what they are.

Hey everybody, I am the guy who is going to get these engines, and as you will see from my online name here I am not a Chevrolet "expert". The info I got from some "so called expert" is that these engines couldn't be used in a civilian application due to motor mount problems. I haven't seen them yet but can't believe that it could be something that couldn't be over come. That is what Tony was really wanting to know, if they are military only. Also is there an easy way to tell a 270cid from a 302?
Thanks,
Jim

GMC motors have the size stamped on the side of the motor by the distributor.
"228", "248", "270", "302"

I believe the block is cast slightly different so you'd have to modify (Grind some off) to get a normal style starter on it.

MONGO

As Mongo as indicated, there are some things one has to do to make a military engine fit in a civie car or truck. They are not insurmountable by any means. The military mounting is removed/tossed and you use the area for the standard civilian application already there. Also as indicated, look behind the distributor area for a number. If there is a 302, 270, 248, 228 anywhere there, then it will fit in a GMC truck with few problems. These numbers also denote the cubic inches of the engine. GMC made other engines but I have not seen or worked with them to add or detract from the availablility of them being able to work in the trucks. Maybe someone else can throw in here. Any news yet on the sizes you have come across? How about the prices?

Thanks for all the information, I have not viewed these engines yet. I was wanting to go armed with the good information I have picked up here. This is one of those deals where we are going through several people to get them. From what I know we should be able to do the deal, it just depends on how much they are and what kind of condition they are in. I only want one of them and I think Tony is in for a couple and the rest will be up for grabs. We will keep you posted.
Thanks to all.
Jim

I'd be interested in one, depending on price. For more 302 info, hit up inliners.org and oldgmctrucks.com. Lots of 302 guys around both sites.

HEY FORDGUY, YOU SAID YOU WANTED ONE MOTOR YOURSELF. DO YOU REALIZE THESE ARE DIFFERENT THAN A FORD 302??? HA,HA,HA!!!! GUESS WHO?

I think I hear banjos playing in the background or is that Pat humming. See ya at the lodge

Dibs on 1.

So, any updates on these engines yet? Runnin out of good weather for a road trip! I may be up for one if the price is enticing to me. How bout you Mongo??

I talked to the middleman today, he said he is going to take himself out of the picture and get me to the owner, after that I will let everyone know how many, how much, and what conditions they are in. I still don't have a timeline yet and with the holidays coming up it's any ones guess when I will get to see them. Did get this information from the middleman however, he said the DUKWs had been re-powered with these 302s (out of the military duce and a halfs that had the automatic transmissions in them) then later re-powered again with 366s and 427s. I will keep everyone posted.
Later,
Jim

Do you think these engines really exist or are they just a "RURAL LEGEND"???

Are these from the DUKWs that run around the lakes near Branson?

They may very well be a "rural ledgend" along with the barn full of old fiberglass cobra replica bodies we were supposed to find out about and the sohc 427 craate motor that never existed. However, we gotta check 'em all out 'cause first time you don't will be the time you miss out. Talked to "the guy" this weekend and he told me where they are located so after Thanksgiving I will be checking them out.
Jim

Need any help? A road trip might be fun, just to see a bunch of old engines! :p

I hope they are real! Please let us know.

I'm in for one if complete and in running order.

If the price is right and they are useable, I might be willing to travel from NC. Anyone in NC, VA want to travel together?

Very tempting. If I had a 302 in my truck instead of a 235, I would probably be interested in keeping it and rebuilding it for more modern cam and better power. I think I saw something about big block Chevy rods being able to work with some crankshaft mods and a wierd overbore for the pistons. That would be an interesting project.

Anyway, anything more on the price?

well now Im interested too. I wont pay 500 for one... but if the price is right, Im interested

the 302s have the same front mount as the 216s right??

BTW I have friends in the trucking business, so I could get a few up here to pittsburgh, pa. If that would help anyone out.

Mac,
The 302 is longer than the Chevy 216, won't just bolt in. On the AD trucks the front frame crossmember is different on the GMC's.
Mongo

Guys,
Too early to talk about prices 'cause first we gotta see 'em and then we gotta negotiate to get 'em. What I intend to do is look them over and take inventory then shoot him a price, trying to average out the good ones with the ones that would be for what parts could be salvaged. Should be able to see them this week. My goal is to get one for myself and I am sure Tony wants one and we will try to get the rest to anyone else who wants one. More later.
Jim

thanks mongo!

Hey Ford Guy, thought I was going to get up to see you but have not had the time. Took the old Doodlebug out and limbered it up the other day. The motor smokes pretty bad and you know what the Surgeon General says about smoking!!! You mentioned after the holiday on the 302's. Do you mean after the holiday season? Because I know it is a hectic time for most people, myself included. Hope to find time to visit soon.

Still interested.

Well, yeah I meant after Thanksgiving, but I am going to extend it 'till after the holidays 'cause you know how busy it is around here. I bet if you put some Sea Foam in that old Doodlebug you could fix anything that is wrong with it, and the smoking too. You know Tony uses it, I think he chases it with Keystones though.
Later!

Don't give up on the 302s! My guy tells me this is a real deal. We are getting close, I will take my camera with me. Can you post photos here or do they need to go somewhere else?

They have to be posted on another server and linked to.

Okay, don't know if I know how to do that, but I will wait 'till I have the pictures before I seek further information on how to do it. Looks like I will be going tomorrow.

Any news?