Welcome to Speier Racing Heads and the home of the VFactor line of cylinder heads! SRH has become one of the leading suppliers of properly designed powerful CNC heads. We have a strong database of dyno proven and track results, look at our results page! Also please look at our track and dyno proven line burr ported manifolds! From NHRA records to working with major cylinder head companies, let our knowledge work for you! Heads are finished per application with many options! We have cylinder heads for NA, nitrous, and turbo applications! From Comp Eliminator to the weekend bracket warrior, we treat all our customers with the same customer support. We use only the best! PAC, Manley, REV, K-Motion, Ferrea, and SRH components. Custom cams and Professional consulting services available. If for any reason you purchase a set of heads from SRH, or have yours ported, and they don't perform like we discuss, send them back and I will work on them until they do, free! Better than any flow data guarantee!