Quote Originally Posted by Dean Ferry
HP500's are alot better engine, that are ~ 470 Propshaft HP, where the 502's are ~390 Propshaft HP, of course these HP #'s are without the Whipple chagers. THE HP500's have way better internals than the stock 502s.
The older carbed 502's are 390. The 502 MPI's are 415.

Thought the 500 and 502 used the same short block, other than cam.
Are the heads the same between the 2 with the exception of 500's are setup with roller rockers? Or different size valves also?