Im not a fan at all of TFS 260 LS3 heads. Ive seen them slow a local car down (408ci) in the eighth mile vs the stock LS3 heads. The heavy intake valves in the TFS LS3 heads is what im blaming for slowing the car down. Car pic above. Real street car.... John Bewely showed where a TFS 260 LS3 head cracked in half on a build. Then Tommy at Mafia Motorsports had the same issue on his turbo cateye pick up. The TFS 260 LS3 head failed and cracked on him as well. Those TFS LS3 castings are trash