Victor ported by Wilson manifolds and a 1050 dominator.

AFR 335's on a 540 in that rpm range are way too big. You'll never get any port velocity and if you're running a 1050 carb it makes things even worse. Only way to really make any power will be with a custom cam...short duration higher lift but that tends to be hard on valve train.

Well that is what I fell into so that is what I will be running. Agreed that port velocities will not be optimal but for what I paid for the whole package I can make it work... Also I am planning on running EFI at this point as I see considerable changes in altitude when I change locations ( greater than 4000' ). The leading candidate at this point is the holly single plane system.

Theres three different cams being talked about here.

139671 (525EFI cam)

236/244 114 LSA
.610/.632

Intake open 9
Intake closes 47
Exhaust open 61
Exhaust close 3

168741 also referred to as the "741" cam.

236/244 112 LSA
.610/.632

Intake open 11
Intake close 45
Exhaust open 59
Exhaust close 5

139021 (cam FBC25EL had)

234/242 112 LSA
.610/.632

Intake open 10
Intake close 44
Exhaust open 58
Exhaust close 4

The 525EFI cam, will hold on RPM a bit longer, than both the 741, and 021. Also, there is more to where the HP "peaks at", than just the camshaft. Cylinder head, induction , exhaust, can play a factor too.

I had a 741 crane in a 540, with iron merlin heads, dart single plane, and 1050 dominator. Peaked around 5600rpm on the dyno.

What are the specs on the heads on a 525 EFI?

Edelbrock 315 CC . Flow is not much better than a chevy iron rect port head.

Valve Lift .100" .200" .300" .400" .500" .600"
Intake 76 146 212 255 294 314 -
Exhaust 70 132 156 181 207 228

Edelbrock marine standard port height, nothing too special. Too lazy to look it up

I see, thanks!

Wonder what kind of increase you could get changing the 525Efi head to the dart pro 1 310 head? Any guess? Or should the 325 head be better?

IMO that's a poor excuse for building a poor combination given all the time and expense you'll have invested before you're done. You could easily sell the 335's and replace them with the right head for your combination. EVERYTHING will benefit from it especially if you're going to see altitude changes like that. A lazy induction makes an engine considerably more sensitive to those sorts of changes. JMO.

In my unprofessional opinion, forced induction would be a better way to more power than heads. Bang for buck a lot better but your XRs might not like them after a while. Or you can just leave it alone :cartman: