Manual 318 Twin turbo

I use a Center force and launch hard at 6500 rpm. I know it is no where near the 750 ft lbs of torque but they are nice. I was told that I should look into an Mcleod soft loc clutch, it is supposed to be more forgiving on launch, that is where you client wants to be I believe you stated.
You might want to give Rob Youngblood a call and ask him, he is supposed to be the guru of clutches etc.

here is a link to his site.

www.advancedclutches.com