What is required to do this work? Is it just the boring out the cylinder walls for the pistons or is there more to it?

 

355 is a 350 with .030 bigger pistons .
30 over is most common size when doing a rebore

 

thank you very much, I'm new at engine rebuilding, I'm learning as I'm going. Project started out as a restoring of a 305 then fell into a rebuild with a 350 from a 93 chevy pickup. I've been getting two different stories on the process of making a 350 into a 355, one is what you stated, and the other includes shaving crank journals, doing something with the camshaft, plus changing the cylinder heads.

 

A 355 is just a .030 bored over 350. Nothing to do with anything else. NEver bore out more than necessary to get the cylinder walls round again. If you can get away with boring it .010 over do it.

 

Pistons require a specific piston to wall clearance. How much depends on the type of piston. Cast pistons need less clearance than forged pistons because they don't expand as much. When a block gets bored out, new pistons are required to maintain this clearance. The pistons should be available at the time the block is bored so the machine shop can measure the clearance.

Ring gap also needs to be measured. Even just honing out the cylinders can cause the ring gap to be excessive. Again, different types of rings require a different gap. Typically .004-.006" of gap per inch of bore so a 4" bore cylinder needs the rings gaped .0016 - .024"