Have you considered going to a flat tappet solid? You definitely have to consider lift with the 1.7 rockers.....as in piston to valve clearance.
With the 4.56's, a little more cam, and possibly a little larger carb, will bring your top end in line. I am assuming this is a all or mainly a track car.
I'll sniff around for a grind that give you some duration, but doesn't put your lift over the top.....If I see something that looks decent, i'll post it up.