ok here is what I have . 2 each 540 cubic inch gen 6 motors, 632 lift 244-256 duration. Gil offshore exhaust . 1050 dominator carbs. Brodix 4500 style intakes. Problem was the dyno run . Hp was only 575 hp at 5200 then it fell. I anticipated abt 625. Timing is at 34 degrees. Any suggestions or opinions. Heads are big chevy rect ports with 230 intakes and 190 exhaust. They flow 322 cc(.Comp is 9;1). My bsfc was .46then .43 at mid range then .53 at top end . Could it be jetted to fat?

With bsfc in the .4's, it might be a little lean. Also, what is your exhaust flow? The cam is pretty mild for a 540 with GM heads. I have a couple of Crane 651's you could try. 244/256 duration, .630 lift both.

My 540 has the same heads but the cam is 680 lift solid rollerand I run a 950cfm.Made 630hp at 5700.torque 650 at 4750.made more hp with less timing,I run 32 total go figure.Im sorry I didnt get the afr heads.

Can you post the actual and corrected horsepower and torque and BSFC numbers? That might help us to figure out what's going on. Please post the jet sizes if possible too.

Ok I have my info in front of me.632 lift 244-256 duration @ .050 (320 intake runners}
rpm trq fuel lb. a/f ratio bsfc horse power
3200 611 168.5 12.6 .468 372
3400 611 170.9 12.4 .447 395
3800 616 194.6 12.5 .450 446
4000 625 207.1 12.5 .448 476
4100 635 210 12.6 .439 496
4500 629 238 13.2 .457 539
4800 614 244.9 13.3 .450 561
5100 589 263 13.3 .475 572
5300 550 278 13.2 .518 555

Ok I have my info in front of me.632 lift 244-256 duration @ .050 (320 intake runners}
rpm trq fuel lb. a/f ratio bsfc horse power
3200 - 611 - 168.5 - 12.6 - .468 - 372
3400 - 611 - 170.9 -- 12.4 - .447 - 395
3800 - 616 - 194.6 - 12.5 - .450 - 446
4000 - 625 - 207.1 - 12.5 - .448 - 476
4100 - 635 - 210 - 12.6 -- .439 - 496
4500 - 629 - 238 - 13.2 - .457 - 539
4800 - 614 - 244.9 -- 13.3 - .450 - 561
5100 -- 589 - 263 13.3 - .475 - 572
5300 550 - 278 - 13.2 - .518 - 555

didn't you run it any higher?? why do you say it fell off if you only ran it to 53?
torque will = horsepower at 5250 rpm I think you had more in it you just cut the test short

I ran it to 5500 the numbers kept going south on us. 4800 rpm 614 lb of torque
561 hp
5300 rpm 550 torque
555 hp

I see your point check the obvious coil bind or the retainers / keepers hitting the guides ( it happens I've seen it) I know it sounds wierd but try a different carb sometimes so;mething is wrong with one we switched a tricked out 1050 to a out of the box one and picked up 60 hp believe it or not ,with the big heads you should not be o;ut of air that early we have printed bigger numbers with a 502 with oval ports so somthing is wrong good luck

I assume he is giving us corrected data anyway, HP = torque X rpm /5250