ah i love competiton products stuffed engines, built one very similar one time, it was in a 71 nova my buddy bought and the 454 in it was a turd, turned out to be bored .030 over at one time and the bore was in good shape but had dished pistons with stock 781s, was probably not even 7.5:1
had a crane single pattern cam in it that was 284/ 228@ .050 .544 lift, completely to big for what it was at the time i think, a performer intake, performer 600 carb, and crap 1-7/8 headers with individual flanges that ate gaskets like candy.
got the same valves you did, had local engine shop guy put them in and do a port job on them, for some reason he left the 1.72 exhaust valves in, idk why, something about the seats couldnt be cut that far or something, buddy who owned the engine dealt with the guy not me so dont really remember the story. i ended up picking a small cam that i thought was big at the time but it worked great, it was an elgin with 224/234 @.050, kb hyper 18cc domes which at the time added $400 to the build and had to fight to get him to buy them but glad i got my way. Had stock rods honed for floating pins, new bearings, and put it back together, i will never forget we put the first 7 pistons and rods in with no issues and on the last one got it started and he told me it was line up so i sent it home and he had is finger in the way and got jamed between the rod and crank and he was jumping around trying to get his finger out and ended up getting stiches, kinda funny thinking back on it now. finished it with an rpm airgap intake, 700 double pumper, hooker comp headers and basic felpro gasket kit.
that engine in that little nova was a riot, didnt mind reving to 6500, with the th400 and ratchet shifter he would shift it around 6000 playing, never seen a track or dyno, i would guess it was 475HP. It was nothing special but lots of fun.