If you don't have an aftermarket block to not only have the added strength but also bore size then I think your wasting your time with these and or similiar or even better heads.
I would be more worried about the block than I would the bore size after flowing my ported 360-1 heads and my buddy’s 245cnc’d heads. I flowed both heads on my 4.010 bore adapter and both heads flowed some very nice numbers. Probably more than enough to hurt a stock block. But then again I haven’t seen to many small block Mopar blocks that have been hurt.
