When using stock steel 4L80E pistons, There is no way too truly blueprint clutch clearances , You have to machine stuff to get EXACT clearance & TH400 Pistons make it all that much easier, As a bonus.....The Work Surface gets cleaned & leveled.
Took .040" off the Direct piston too fit 6 .080" Frictions & 6 .077" Steels at .057" clearance.
Took .120" off the Forward Piston too fit 5 .080" frictions & 5 .077" Steels at .045" clearance.
Direct piston...
Forward piston...
