Just bought a 428 power unit with the intention of putting it in my 74 f--100 to replace the tired 360. Anyway, someone had put ft heads and intake on it at one time according to the casting #'s and the exhaust crossover and exhaust manifold bolt pattern. Anyway broke the engine down and it truly is a 428 has the 1ub crank and the cj connecting rods. Also had the 9.5-1 compression pistons. Anyway have a set of rebuilt heads with matching valve springs for a performer cam. What I'm wondering is the balance of the motor. They flywheel was externally balanced and the harmonic balancer looked like a no balance unit ie. no counterweight or offsets. Anyway this is going to be running a c-6 so what flexplate do I need for it? Will the one off the 360 work? Any information would greatly be appreciated. Thanks again Aaron