Re: Internal or external balanced flexplate
Well the 400 SBC is an externally balanced engine. Which requires an externally balanced flywheel and its mating Harmonic balancer. No other small block (that I am aware of) is externally balanced. If the 400 that you have was rebuilt as an internally balanced engine, then you could use the parts from the 305, otherwise No, you can't. If the 400 engine came with a Harmonic balancer, you should be able to use it, as long as it is for an externally balanced engine. Since it came from a 4 speed car you can not use the flywheel. You need an externally balanced flex plate. You can buy aftermarket flex plates that are 168-tooth or 153-tooth.
69 Camaro -originally a LM1 car. 327, Edelbrock E-streets, hooker, DUI performance distributors, ultradyne cam, stewart, TRW etc. Vintage Air, AGR steering, Corbeau GTSII seats, 700R4 transmission, 12-bolt w/Eaton 4.11:1
Last edited by TJS69; Oct 9th, 09 at 06:07 PM.