In addition to that mentioned, I would verify what camshaft you have. You can get a rough idea with a dial indicator at the valve. I see they offer 2 versions of their RPM kit now, 400 HP and 451 HP, with the main difference being CNC ported heads, camshaft, and an Air Gap intake. I'm not sure how you could determine CR, but you could pull the intake to see if the heads are ported. 1 3/4" headers and a 2 1/2" exhaust with free-flowing mufflers MAY help a bit also.
'65 A-code coupe, T-10 4-speed, 8" 3.25 limited slip