So currently rebuilding my first 4l80e. Have a performance rebuild kit with all the billet goodies and what not. My current predicament is the forward clutch stack. This transmission is a 95 year model and came with the aluminum piston in the hub and the coned style cushion plate. At first I replaced the aluminum piston with a bonded style and this is when the problem first appeared. With the bonded piston the clutch stack was OVER the ledge. After some thinking I went back to the aluminum piston to see if it was shorter and it put me to about even with the ledge with the new frictions and steels. For a test I put the old frictions and steels in and it measured 0.035” below which would be within spec but I assume this is from friction wear as all the steels are 0.77” new and old. What is the best call here? I’ve heard some people are wary of the steels that are thinner than 0.77” due to heat and considering this is going to be in a performance build with a brake I would assume this might be something to take in to consideration? I’ve also heard of getting rid of the coned plate and replacing it with a th400 waveplate which would go directly against a friction and therefore ridding yourself of one steel and adding the difference back in the thicker steels? Thanks in advance and please bear with me as I’m learning lol

 

I would ditch the coned plate and replace with th400 waves, I would not run a clutch against the wave, Wave then steel I actually use two waves then a steel.
As for FWD steel thickness, While always great to use thickest possible, Truth is the FWD is a static clutch in all fwd positions (always on) so heat is really IMO a NON ISSUE in this set .
So I would go with two waves alined, steel thick here if poossible Then normal stack and use whatever thickness steels you need to get the clearance you are shooting for ,