When I assembled the bottom end of my stroker, I noticed that the nuts for the rod bolts come awfully close to the block, even though there isn't any contact anywhere with the cam installed. My machinist clearanced the rod bolts further even though they were already stroker design 4340 I beams. My crank is a GM/Cola 4340 3.8" stroke crank that I had rebalanced for an LT1, and the motor was originally intended to be used with studded PM rods in a std. bore block with no additional machining (GM 383 crate engine). I didn't take into account that I assembled the engine with different rods. What is this clearance supposed to be?

They come so close to the block, it looks as it the nuts would make contact if I backed them out a little bit. Can't see light past them, but they dont make contact anywhere!

 

I wouldn't sweat anything from ~.030+ (.030 being about the width of a credit card). Of course it depends on the crankshaft... some flex more than others (cast vs forged) and what you plan on subjecting the engine to.

-Mindgame

 

I am using a 4340 crank and rods, limiting the engine to 6400 RPM, and daily driving it. Wont see over 3000 much.