piston to wall measurement

Yes. However by the time you do that and have good rod bolts installed and have the rods resized, you could have bought a whole new set of rods with good rod bolts and already bushed.

So if want my kb pistons to have full floating pins i would have to have the pin hole in the stock rod bored and use a bushing? Thanks

what I did with my 318 is I went to e-bay and bought a set of 340 full floating rods to avoid that machining cost. you might could find a set of "B" or "RB" rods there.