The info I ran across was dated some.But it was confusing at the sametime.Basically it said the NASCAR engine builders come up with some real oddball combinations.That during their R & D they even have blocks that use a different bore size in the same block and found something there for more power.Like the first two bores that have one piston size different than the others.Huh??. I don't know if that is total B.S. or what it would be that they found.

Maybe Dave or one of you guys could jump in here to explain this.Yep,just curious.

Oh it was about a boat load of those NASCAR heads around still good but cheap and why they couldn't be used on OEM blocks.Custom blocks with bolt holes moved and bore spacing not the same,etc,etc.