I have a chance to buy dart Sr heads with 202 valves..will they have enough clearance on a 351 1969 motor with stock pistons,,the cam has 550 lift?? thanks
It's not the total lift you need to worry about but how the total valve timing events have an effect on piston to valve clearance. Namely on the exhaust and intake stroke follwing it. In the exhaust stroke, the piston is chasing the exhaust valve up the bore, then around TDC, as the exhaust valve is closing, the intake starts to open, then chases the piston back down bore. 2.02 intake valves usually don't fit the clearance notches in the stock pistons, that too comes into play.
2.02 heads are generally NOT trusted on an engine with stock pistons and .500"+ lift cam. Your combo might, but using the 'safe' rule of thumb, you probably should plan on pistons or at least mods to your current pistons. Which ones? If you are refering to the stockers, there are better heads out there than those. Especially the 69-73 351w heads after they have been ported. Those heads have been proven to outperform some aftermarket heads after professional porting. Labor cost and weight are the 2 big drawbacks for any stock iron head.
For my part in the thread... I don't like resurrections either. However, my response was to posts from yesterday.
