Re: Boring out a 402
Check the distance between cylinders by looking thru the center core hole. Paul got it partly right - a wooden pencil will barely fit between the cylinders of the thick wall blocks, but as Dan said, that's not a guarantee it'll go 4.250 - but some will. The problem with that is it'll call for custom pistons. If it's more like 1/2" between the cylinders, you'll be limited to about .060 over.
If you don't have much wear, ask the machinist if it'll hone another .010 with straight, round cylinders.
The correct spelling is HILLIARY