Engine swap ?

[ClassicJimmy]

I have a 92 K2500 ECSB w/196k miles on it. I have a 75 GMC K25 w/a blown engine. Both trucks have standard trannies. I want to put a new engine in my 92 so I can go another 200k. My question is, can I put the 92 engine into my 75? I would be converting the 92 intake to carberated to put in the 75. I'm wondering about the rear seals, flywheel, balancer, & the mating to the tranny. Is a bolt in or am I asking for trouble? Thanks for the input.

[beaterC10]

A few possible problems come to mind.

1. The 92 block likely is not drilled for a mechanical fuel pump.
2. The dipstick on the 92 is probably on the opposite side from the 75. If it is, it won't clear the exhaust manifolds from the 75. At one time you could get spacers that installed between the head and manifolds to get clearance for the dipstick or you could install headers.
3. You will have to modify the 75 intake to fit the 92 heads, not a huge deal.
4. The 75 damper should install ok on the 92 crank, but there might be some issues with getting a timing pointer,front cover, oil pan combination that will work. Chevy changed the thickness of the seal that mates the timing cover to the oil pan sometime in the early 70's, I think the change was in 74. Might be able to use the 75 damper and 92 front cover with an aftermarket timing pointer.

I ran into some of these issues when I first installed a 73 vintage 350 in an 81-87 truck. You just need to expect some challenges when you cross pollinate between different decades.

[ClassicJimmy]

Thanks beaterC10, I had not thought of those issues. Not sure how motivated I am, but the 75 will most likely be a "going to the dump" & "snow plow" truck for my in-laws.

[ClassicJimmy]

Just curious....... If I use headers for the vintage engine block I'm using, wouldn't that fix the oil dipstick issue? Also, can't I use a manifold designed for a carb conversion on the 92 block? I can use an external in-line electric fuel pump, right? As for the rest, I haven't done anymore research, but any advice is greatly appreciated!

[beaterC10]

Originally Posted by ClassicJimmy

Just curious....... If I use headers for the vintage engine block I'm using, wouldn't that fix the oil dipstick issue? Also, can't I use a manifold designed for a carb conversion on the 92 block? I can use an external in-line electric fuel pump, right? As for the rest, I haven't done anymore research, but any advice is greatly appreciated!

Yes.

The timing cover may not be an issue at all. My problem was in using the 8" balancer that came with my 73 vintage block. The original 73 timing cover had the pointer at 2:00 o'clock, but the cover was shot. The mid 80's 305 from the truck had a smaller damper with the pointer at 12:00 o'clock. I ended up using an aftermarket pointer and cover with the 8" balancer. The only issues with the aftermarket stuff was that I could only find chrome, and it starts rusting as soon as its installed. I had these issues when I put the engine in an 83 305 truck. I also had some issue using the stock carb linkage with the Weiand manifold I originally used, no problems with the Edelbrock I replaced it with.

I just put this same engine in my 86 GMC 4.3 truck. The issues there were moving the starter wiring to clear the headers, changing the engine mounts and cooling.

[ClassicJimmy]

Thanks again, beater. So there were no issues with the tranny or anything of that nature? Both blocks were mounted to std trannys, the 92 to a NV4500 & the 75 to the NP465 (?). I'll use the flywheel & clutch from the respective trucks, just want to know if thats ok. Again, thanks & I'll check into the timing cover & pointer issue later today.

[beaterC10]

Originally Posted by ClassicJimmy

Thanks again, beater. So there were no issues with the tranny or anything of that nature? Both blocks were mounted to std trannys, the 92 to a NV4500 & the 75 to the NP465 (?). I'll use the flywheel & clutch from the respective trucks, just want to know if thats ok. Again, thanks & I'll check into the timing cover & pointer issue later today.

Shouldn't be any problem with the transmissions. You won't be able to use the 75 flywheel on the 92 engine and vice versa. I have noticed in a lot of parts listings the clutches are different pre and post 1984. I don't know what the difference is.

[SSC's76]

The clutch difference is most early clutches are 3 finger borg&beck borgwarner the newer ones are diaphram which are mucho better IMO. The passenger side dipstick will actually work perfectly with the older exh manifolds since the 70's ones will clear either side dipstick but the newer 80's LOG manifolds would need the adaptor or some creative modifications to clear.