P.S. the HO 305 of the early 80's had an option of 1.91 intake valves. Very hard to get OEM but aftermarket can supply them. I don't think you need to go there yet. Factory 4bbl intakes were 1.88. Sufficient for street use on the combustion chambers you have. I would however recommend stepping up to a larger exh valve. Probably a 1.6. It will help enough to give you a good feel for what you want.