How much can valve head OD be cut?

toolmanmike said
Next question for me, how large are the chambers on those alloy heads? (diameter wise not cc wise)

Bigger than the bores.... like the 675's used on 2 BBL 273's. But I cannot give you an exact number as I don't have a set right now. I don't see a reason to fret over the chamber overhanging the block.....

Here is how close the valve is; I simulated a 2.02" valve by carefully pasting a 2.02" diameter paper disc to a 1.78" valve in a 675 head. The 273 block is stock bore.