Touring auctions and digging through junkyards for a good set of Vortec heads can get old. Pro Torke Vortec Heads are designed as a stock replacement for the popular GM 906 casting but flow far better and are much more powerful. RHS patented Clean Cast Technology and close tolerance machining provide exceptional finish quality for superior performance and reliability, and the revised water jacket design helps prevent cracking commonly found in GM 906 factory castings. And when you add up the money you spend repairing and machining factory heads, these heads actually save you money - giving you maximum power for your performance dollar.