The Stovebolt Site Forums The Shop Area Engine Shop big blocks

anybody familiar with dropping a 366 chevy big block into a 1966 c20 2wd? need info on where to start for motor mounts. this will be a manual transmission in case that matters.

I put a 454 in a 67 GMC one time in place of the V-6. I had problems getting exhaust to clear the frame, but that was about the biggest hurdle. Not sure but I think the frames on the 66 and the 67 are close to the same size.

I also had to rework the fron engine mounts, but don't remember that being a big ordeal either.

Good luck.

I have a 66 C20 and I was thinking about doing something similar. I had a '74 GMC 427 from a cabover(same block as 366) which I have since sold. It had side motor mount bosses, so it would have been a direct bolt in. My 66 has a 283 & SM420. If you have a 6, you just need to swap the motor mount to frame brackets with a V8. You can use the flywheel & clutch from a regular v8. The 427 exhaust manifolds wouldn't work because they covered the engine mount on pass side. Regular big block manifolds or headers should work. The only other issue was the water pump. The outlet was 2.5", so I would need a reducer to the radiator. You might not have these problems depending on what the motor came out of. Good luck.

Isn't the 366 a "tall block" engine like the commercial 427? It's good for lots of torque, but the gas mileage will be like pouring from a 2-gallon bucket into the manifold without a carburetor, and the power will be somewhat less than a 350 small block. Too much weight, low horsepower, and lousy gas mileage- - - - -not a lot to reccomend it, IMHO.
Jerry

Yes, the 366 is the same block as the tall deck 427, just a smaller bore. Great torque engine, especially in a 2 ton (which is what it was meant for), but like you say, no good for a pickup.

Yes, I agree. A small block is a better idea. A 366 wouldn't be a good match with the 4.11 rear either. Unless you want to stay under 50 mph. That's why I sold the 427. The buyer was going to bore it way out, change out all internals for light weight parts, & put in a drag boat. If you wanted to be different, didn't drive it much, & didn't care about practicality, then I say go for it. You can always swap it out later.
Scott

thanks for bursting my bubble! actually i appreciate all the advice. i only drive it about 5 miles back and forth to work. i thought the big block would be something you wouldnt see everyday and have a 366 available for free but sounds like it might be a poor match. with the straight 6 and the four speed i top out about 45 mph. any suggestions on rear end to use with a v8 to get this old girl up to highway speeds?