Larry
I can't understand why you need to notch the block Or the lower half of the head. Notching the upper push rod hole comes into play when you start run a 700 lift or bigger,Or go to a 3/8 dia push rod,or go to a 1.8 rocker or again bigger It wants to Pull the push rods into the head. Even with a two peice push rod I have not heard of anyone needing to cut/slot the block.
As to valve size i have seen a 2.0 valve in the head. But I don't think you can go any bigger in dia. And your talking about doing more work to unshroud it. But I know Glen Self and them guys Have moved the Valves around in the head. off set the vlave guides now as to how much ,that i haven't a clue.
And as for the space/casting thickness from push rod to push rod
hole in the head (gasket & block area) kinda varys in thickness
from just looking at the cut heads i have. So i am not sure how
difference there would be in the Blocks in the same area.
But the blocks have beeen opened up to a 5/8 hole when running a HIGH lift cam with 3/8s push rod you would also need to make a releaf cut in the block itself. You can see a photo of that in Leo's book on page 79.
God doesn't like ugly.
