I dont think you will see any overall HP gains to justify the cost of doing the swap. The power levels between the 2 heads and intakes will be similar. The early B heads (96 - 98 Cobra) actually flow better then the later C heads. Under boost you would do better with B heads. They make most of their power at upper end of the RPM band. The later 4v heads make better low end hp and torque compared to B heads. They work well with boost also,.. but for all out RPM hp,.. the B heads are a better choice in my opinion. On the street you would probably do better with the later heads because of the broader torque curve. But if you compare dyno graphs the later heads fall off earlier then the B heads do.

Get with Bitmark or BVH on this as both of those guys have a lot of experience on these motors. I know my way around them,.. but I am by no means an expert on them.

Have you tried extrude honing or porting your intake? Someone correct me if I'm wrong,.. but I doubt cams on a 4v will cause even a stock intake to become a flow restriction. 96 - 98 4v motors are very limited on cam choice because of PTV clearence issues. Have you had it tuned with the new cams? Did you degree the cams in? If not,.. theres a good bit of power lost right there. Are you still running IMRC plates? What kind of TB and air intake are you using? Are you NA or running a power adder?

The 96 - 98 motors are pretty good. A small shot of spray can bring them right up to the ragged edge of reliability. They have a forged crank,. but still share the weak rods and piston that the GT's used. Anything above 425 - 450hp is borrowed time and on a small blower or NOS they can easily reach that number.

If you decide to do the swap,.. its pretty straight forward. You dont have to switch to COP ignition,.. you can still use your coil packs and stock wiring.

Hurst