Here's my recent experience. My car is very similar, only drivetrain difference is I have 3.50:1 gears. I used to run a Ford M6250A341 cam which has 510/536 lift & 214/224 duration at 50thou. I had a Performer & a 3310 (750VS) Holley. This was really tame! It delivered easy driving bottom end, you could make a sharp turn in top gear & drive off normally! Not really what I wanted from a musclecar with a stick, I want to work it & be rewarded. After driving round with a 429 with similar cam (lame top end, 14s/98 quarter mile) I recently put the 351 back in with a better cam & manifold. I reasoned if 0.5" lift was tame but 0.6" was race spec then I wanted 0.55" & figured I wanted to go up on duration to about 235/245. I struck lucky as a guy near me was selling a brand new Lunati solid lifter cam (41107LUN Grind SP02-305) 0.55/0.559 237°/247°LSA 108. Quoted Rpm range is 3200 – 6800. Basically with a 351C 4V it appears that if its cammed for 5500 rpm you will have 350 hp & if it can make 6500 rpm you will have 450hp. That's how the heads seem to work. I also got a Performer Air Gap at a good price, I am still tuning & because I am using a "too big" carb (850DP). I have just blocked off the plenum divider cutout, which is a crutch for a small carb. Prior to this the air/fuel ratio was all over the place but even so when I gassed it at 3000 rpm it pulled really hard, made me grin & I have not been above 5000 rpm ish so far as I'm supposed to be running it in. Looking forward to the next test drive/tune session this weekend. Get a good cam, ditch the Performer, don't look back!