[milner351]

Guys
You are all right in my opinion. Except that nobody mentioned building the whole car as a system, if you are going to race this car, you need to think of the complete package...

I would buy a "desk top dyno" program, and put your intended combination into it getting the best flow numbers you can, which the manufacturers provide, put in several different sets of cam numbers (garbage in garbage out) (the cam disk comes with billions) and lay the torque curves generated by the program on top of each other... to see how the different combinations lay out.
THEN
Think about your gearing, tire height, axle ratios, etc, and figure out where in the rpm range you really want your power to be, while keeping in mind the higher rpm you go, the more $$ you'll have to spend on valve train parts and balancing.... and in general, the shorter the lifespan of the engine....

I am running trick flow twisted wedge heads out of the box on a efi 5.0 mustang with stock cam, T5, 3.55 gears, and after market exhaust, with the stock short block, this car turns low 13's all day, while driving too and from the track with all the power accessories and AC. That's nothing compared to any of your cobras but for a car that weighs several hundred pounds more and is severly traction limited, that aint too shabby.

The trick flow heads are nice, but the AFR's are KING in many comparisons, for a vintage racer, I'd probably go with the 185 AFRs. You'd be hard pressed to out flow those heads in the rpm range you speak of, and they don't need any porting, just bolt them on with all stock location intake and exhaust.

Also, make sure you check your valve train geometry, your springs match your cam and are the proper height installed (the springs on the heads when you buy them may not be good enough) and 'clay' the set up to make sure you have adequate valve to piston clearance, UR talking some serious compression here, it might be close in the 'eyebrow' of the piston fly cuts for the valves....
it's always something.