Cylinder Bore

I bought a late model 351w block that has been bored .030 over, and I have a set of JE SRP forged pistons for my 408ci stroker kit that are also .030 over. Should I try to get a set of pistons that are .040 over so that it is possible to hone the cylinder to the piston or should I just put the engine together with the pistons that I have?

The block is freshly bored and hasn't been run.

stonecoldtx said:

Hi, Gailahan--

Actually, the best procedure would have been to supply the pistons to the machine shop, so they could fit them to the cylinders--i.e.: hone the cylinders so that the correct piston-to-cylinder wall clearance was obtained.

Click to expand...

That's what I was saying. The machine shop I bought the block from is not the one that I'm dealing with... I bought the block from a machine shop in Maryland b/c I wanted a late model roller block, it was a good deal, and the majority of machine work was already done. (hot tanked, magnafluxed, decked, etc...) The only problem is that it was already bored .030 over. I already had the stroker kit with pistons that are .030 over. So, in order to hone the cylinder to the piston size I would need to acquire .040 over pistons. My question is, should I not worry about the cylinder being honed to the piston size and just use the .030 over pistons that I have, or should I try to get .040 over pistons so that I can have a machine shop hone the cylinder to the piston?

stonecoldtx said:

If you have precise measuring tools, you can do that yourself--just measure each cylinder bore and measure each piston skirt.

If the difference between the largest cylinder wall diameter and the smallest piston skirt diameter is beyond the maufacturer's recommended piston-to-cylinder wall clearance, you will need new pistons, so that the correct clearance can be obtained.

Click to expand...

JE has a PDF that says that for SB applications with a 4.000 to 4.200" bore there should be a minimum piston to cylinder wall clearance of .0025 to .0035". I'm going to bust out the Micrometer and see if I am within this range. Hopefully I am and I can use the pistons that I already have. If not I guess I'm going to try to get .040 over pistons.