i don't understand all the bad rap about procomp heads.i have had 2 sets with no problems. sure they are not the best,but what other head can you get for 650.00 (skip white)and run pretty strong....never buy them direct. i get them from a local speed shop,bare. he puts manley valves,comp springs and 10 degree locks on them. a set of 210,cnc with roller springs go for 1000.00...the new castings,claim to take care of any cracking problems....he did a test with them on his 3200 lbs nova,406 sbc....best with 227 cnc, afr heads was 10.00-1/4 mile....then put the procomps on with the same comb. chamber..the car went 9.90. they can't be that bad...on the other hand,i would'nt put there rocker arms on a lawn mower.fuel pumps either.