The Stovebolt Site Forums The Shop Area Engine Shop rebuild suggestions needed

I have two Chevy 235 engines one was in my truck the other was donated to me. I started tearing into them today to see what I have.

Block number one has been bored to .060 and has some vertical scratches in the cylinder walls. The pistons look like new. The main and rod bearings appear to be .010. The cam shaft looks like new it also has some spots of orange paint on it. (Does that mean anything?)

Block number two has been disassembled for a while. There is surface rust on the block deck and in the cylinders. The cylinders appear to be standard sized.

So what should I do?
I was thinking the best bet would be to clean up the rusty block. Would it be foolish to over bore that block to .060 and use the good pistons just because that is what I have on hand? I think it would clean up fine for .010 pistons but I would have to buy the new .010 pistons.

Also if someone with an old parts book could you verify the size of some bearings I would appreciate it.
Rod bearing markings ….GMML…8771.…187N5
Main bearing markings….GMML…8779.…160B5
I think they are both standard size but it would be nice to know for sure.
Thanks.

Use the rusty block have it bored the minimum to clean it up all the rust will disappear in the machine shop.a friend of mine lets all his spare blocks for his race car lay out in the weather and get good and rusty(he calls it seasoning the block).as for the crank you can get by with turning them .030 if necessary after all your not building a high winding race engine.

I agree. Use the seasoned block. You could have the block decked to increase compression and overbore the cylinders. Have the block hot tanked to clean everything up. If you build it right, you can get 300+ horsepower out of it.

I'd try to use modern pistons and rods, rather than using the heavy stovebolt slugs. I don't know the standard bore size of a 235 and can't seem to find info on it anywhere either. But you may find that with some wierd overbore like 0.035" or whatever, you can use small block Chevy pistons. Then play with your rod length to get the right compression height, using modern rods. Once again, I don't know the crank journal size at the connecting rods, so you'll have to work with a machinist. But turning down a crank, or welding it up to a larger size and turning it down, is not expensive and is commonly done to restore cranks. You could probably get the journal size to work with a modern forged connecting rod.

Lots of modern cams are available for these motors, and they take standard hydraulic lifters. And you can get a great flowing aluminum head now.

I'd suggest picking up last month's issue of Hot Rod (I think it was) or checking it out at the library. They had a series on modernizing the Chevy I6 for V8-level power. Although it wasn't a 235 they featured, I don't see why you couldn't modernize a 235 as well.

Cliffords might have stuff to bring your 235 into modern technology. From the outside, you could look almost stock, except for induction and exhaust. Internally, you could be shifting at 6000 rpm and running like a scalded ape.