I have a set of BBC cylinder heads from 1972. They are factory stock with 113cc chambers and 2.06 intake valves and 1.72 exaust valves, casting # 353049. When i build the engine its going to be a 496 stroker with all the goodies. I was wanting to find out if these heads are worth building or are they junk? If they are'nt good what would should i get?This is going to be a street motor for the most part with an operating range of 1800 to about 6000 rpm. Any help is much appreciated