I probably have the only GER Thunderbolt 3500 stall converter that GER got right! For a 904, no less. I did crack a pump drive, which I got replaced with a chrome-moly one, but my lowly GER has went 30K+ street miles and at least 400 low 11 second motor passes, plus a handfull of 10.60 at 130 - 1.42/60' passes on a 100 shot. 360LA engine, low gear set 904, 3.89 gears, 3150 race weight. I think they called it a 3500 stall 9 3/4" - I can usually hold it to about 3800-3900 on the line. I've tried 2 other "name brand" 9 1/2" 3500 stall converters, and both were tighter at idle and slowed the car down about 3 tenths. I know the next pass may be it's last, but it was the best $269 I ever spent on race car parts. We bought 2 more of them after I bought mine and GUTTED them in 12.50 cars!