I agree with yellow rose on his recommendation for a Mcleod Soft Lok clutch setup -flywheel, sintered iron disc, and adjustable pressure plate. I struggled with 4-speed racing for quite some time, breaking this and that, missing shifts, etc...
In the end I was having success using the Soft Lok, Liberty pro shifted gears, and a reverse lockout on my Hurst shifter. And I still ran a braced 8-3/4, 4.86 pro gear without issue after breaking a bunch of stuff earlier. I would take the Soft Lok recommendation seriously. It's the only way to go IMO.