You can get different thickness snap rings, and even a thicker thickness steels to adjust clearances. I think turbo 400 snap rings will also work? I don't know the best place to get them. But this seems like a good price at MACKO:
http://www.makcotransmissionparts.com/A727SnapRings.htmlI haven't used the Raybestos clutches, but I'd think the clearances would be about the same as stock?
The rear clutch is not a shifting clutch, when in drive it is always engaged so the clearances can be on the tight side. Factory spec for 4 clutches in rear pack is 0.025" to 0.045" (I just think of it as 0.030" +/- 0.005").
The front clutch engages third gear (a shifting clutch) and the clearances are larger. Factory spec for 3 clutch pack is 0.035" to 0.088", 4 clutch pack is 0.047" to 0.110", 5 clutch pack is 0.033" to 0.075".
Not sure if the tighter spec for the 5-clutch is because it uses all 12 of the return springs, has a higher second band lever ratio, and there is also more material to compress?
Using 0.020" per clutch works well for the 3 and 4 clutch setups (0.060" and 0.080".)
On the 5 clutch, I would still stay on the larger side, maybe 0.060"?
Hopefully someone who does more of the 5 clutch setups will chime in.