I have a 440 engine with bad 906 casting heads on it. The heads had some "porting" work done to them and subsequently started to leak. I have a set of 516 heads and would like to use them as opposed to buying another set of 906 or whatever. I still would need to have machine work done regardless. Anybody see a downside to using the 516's over the 906's . The car isn't exactly a rocket but has a fair amount of power (430-450 hp range.) Thanks heaps.

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