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Hello everybody. I am brand new on here. Here is my dilemma that I would like some advice on. I am not a mechanic and the person helping me is being kind of vague.

I bought a 1950 GMC 150 (1/2 ton long bed) that with awesomely patinaed black paint and a very solid body and frame. No motor/transmission to it. I bought it as a donor for a much rougher 52 GMC 3600 that I plan doing a LSx restomod to. But, I am falling in love with the look of the 150 and am thinking of doing just the bare bones basic stuff to it to use it as a mostly local driver. So, it needs an engine/drivetrain, electrical, and brakes at least.

The 3600 has whatever size of straight 6 in it (red painted cover if that helps) that was rebuilt in the 80s but it was given up as a father/son project and it was never fully reconnected in the truck. It was stored in a barn until the father passed on which is how I acquired it. It turns freely but I am guessing that it should be gone through one more time with the gaskets getting replaced due to sitting for 30+ years. The truck also came with a spare GMC 6 cyl motor from the same era that has a blue cover. That engine looks rough, but complete, and it still turns by hand.

So my dilemma. . .

I wish to put a straight 6 back into the 1950 GMC. I am wondering if I should put the engine from the 1952 into the 1950. Or, is there a better straight 6 to use that will be easier to rebuild or find parts for in the future. What do you 'experts' of this era recommend?

I am also wondering about what newer auto/manual transmissions may best compliment the AD engine (or whatever better straight-6 is recommended). Or, should this be asked on the drivetrain part of this forum once I make a decision? I read an article in Classic Trucks magazine about sticking a T5 or TH350 on a 216/235 to make it more modern road worthy but they did not mention anything about needing to use adapter plates or whatever to make it work. Or, if rear gearing (or the whole rear end) should be changed with such modification.

Any insights would be appreciated. Thanks.

Paul,

Welcome to Stovebolt.com.

There is no 3600 model GMC ("52 GMC 3600").

You might be referring to a GMC 150 series (3/4 ton truck)?

There is a GMC 102 series 1/2 ton longbed (same size bed in a 150 series GMC and in a 3600 Chevrolet).

What 6-cylinder engines are you referring to?
GMC (228, 248, 270, 302) or Chevrolet engines (216, 235, 261) - you might want to designate make and cubic inches.

228 GMC ^^^^^^

I would just get an SM420, that came with them when new. They are fairly easy to find and you will have no exotic problems getting the truck back on the road. You need to go through the casting number search to pinpoint what engine you have first. That is an easy search. Depending on your exact truck, the rear end upgrade, new gears, may be the easiest route to a little more speed in high gear.

If you have two engines that spin, do compression checks and possibly start them on a stand and see if they are any good. Everyone here seems to like the leak down tests as well. The engines will both most likely need some internal cleaning. My guess is that both are going to run and would work. I would tend to put the GMC back into the GMC Truck if possible.

I would also guess you have Huck Brakes. They too will work fine but require more care and maintenance than newer brakes. You just have to learn about them.

You have a lot of options.

The displacement on GMC's starts with the SN, stamped on the r side just behind the distr., I.e. 228xxxx.

Chevies, not so, GMC are slightly longer, so a Chevy in a GMC engine compartment will look unusual.

Ed

Ok, my 52 GMC is a 3/4 ton long bed whichever model number it may be. I thought that I had seen 3600 on one of the old registration cards so that is what I have been calling it.

As for which 6 cylinder engine I am referring to. . . that is what I am trying to get advice on as to which one will be best for me to put into the 1950 GMC for ease of repairing/rebuilding it to put into the truck for for future repairs.

Thanks for the info. Both engines are GMCs. I have the manual transmission in the 52 as well as a spare one that came with the spare motor. They must both be what you are talking about.

I have heard about kits for swapping out the rear gearing to something a little better for modern driving but so far I have not found out who is selling them.

I have no clue about the brakes other than that they are drums. I am looking into the brake conversion kits but that isn't a priority yet. I am keeping the straight axle on the 50. (A dakota IFS kit will go on the 52)

I think a better question is: will the 1952 GMC engine and
transmission fit in the 1950 truck.

To me keeping things original makes things easier. I think
the 50 and 52 engines are the same as far as dropping in and
not having to change anything.

Those that know will set you and I straight. Jeffrey

Any 228, 236, 248, 270 or 302 will bolt right in to the same hole. Later ones will need the front mount changed to fit in an earlier truck.

I found the numbers I think but it doesn't make sense if the smallest GMC size is a 228 plus they both appear to be on the drivers side so they are not on the same side as the distributor. The two SNs are 2136477 with a AY under it. Also on is a "A3 1". On the other engine is 2194819 with a B under it and "F9 3". GMC is stamped onto both of them

I just found out the info on my engines. The one that is in the truck has casting numbers for the 228 but has a block that was made on November 24, 1952. That seems late in the year for being an original engine for a 1952 GMC. As for the spare engine, I missed seeing a block casting number on it but the heads casting # was used for a 248 and it was casted on June 9, 1953.

Just my 2 cents... I have a 1953 GMC... any of the engines will be fine, make sure they have good compression and oil pressure. I would run either a modern T5 or a 700R4 transmission. I would put a modern 4.10 rear end ratio in the trucks. And the huck brakes are coming off mine next week in lieu of disc brakes. They can be a real pain to find drums for and they manually adjust.

I am probably going to use the 248 because of the little bit of extra power it will have. I have a 700R4 core that I am going to get rebuilt for it. Was the 4.10 rear end a kit for the original or did you use a whole new rear end?

The numbers you need to look for are stamped, not cast, on a machined pad directly behind the distributor. The first three digits will identify the size of the engine. The same bellhousing that bolts to a Chevrolet 216 or 235 engine will fit all the older GMC sixes, 228 through 302. If you want a modern design automatic transmission such as a Turbo 350 or a 700R4, an adapter plate and some modification of the crossmember at the rear of the engine will be required, plus a rear support for the transmission will be needed. If the current rear end uses an enclosed driveline (torque tube) then the rear end would also need to be swapped to accommodate the automatic trans.
Jerry

Mine had an HO52 so I just swapped out the center carrier. 4.11 center carriers are getting scarce, though. If you can't find one you will have to swap entire rear ends.