I have an 05 GTO that I want to get rid of my M6 and put a TH400 in. I currently make 435rwhp 395 rwtq. The powerband of the motor is 3800-7000rpm with the 242/248 .621/.615 on a 111 cam. I also want to get a 150 wet shot down the road. I currently run 3.42 rear gears and a 26" tall tire.

Based on my powerband I was thinking of going with anywhere between a 3500-4000 stall.

But which STR would you all suggest? Based on the GTO notoriously weak rearend I don't want to overwhelm the rear, but I still want good 60 ft times.

 

I've been researching this and it seems if I have a car that is more suited to top end power I want to go with a lower STR converter?

 

Yes the higher str, the less efficient it is up top. A good str number for up top is 1.9-2.1