I tried a PTC and a Dynamic they worked good . But I had Coan build me one. It was quicker by .06 and faster by 1.5 mph than the other two. But the Coan cost $350 more. It stalls about 5200 rpm and drops about 400 rpm on the shift. The Coan people guaranteed me that their converter would be quicker and faster. And they were right. But it might not be worth it to most people. But we're trying to run 5.90 with a standard style LA head .