I finally got a hold of Fred at Mcleod and his service was ten fold that of what I had previously received. He was actually very helpful, interested in the project and spent some time making sure everything would work together. If you call Mcleod use ext. #236 and just go straight to Fred, it will save you time and headaches.
I am going with a aluminum flywheel street twin disk clutch for a 454 application (2-10 3/8" disks and 1200hp capacity) 63001b-2c-07, adjustable dowel pins for my Lakewood bellhousing 860-625, a LS1 input shaft for the LT1 T56, a Mcleod adapter plate (4sp bell to T56) 8-207, adlustable ball stud 16908,.
This allows a standard style 26 spline clutch, aftermarket SFI scatter shield, mechanical 4spd clutch pedal/linkage, and of course two extra gears , plenty of holding power with a driveable clutch, and a simple installation. Best combo I could come up with after a weeks research and exploring all options, including machining my own adapter parts, for my application and I have included Mcleod part numbers in case any body wants to run a similar setup (you can sub the clutch for a cheaper one and a stock flywheel). Cost is approx $1500+ a T56 (got mine for $800) $2300 total - $700 (selling M20)- $300( selling LT1 iput , bellhousing and clutch). So for $1300, $300 more than a new twin disk for the M20 and a lot of labor I am getting a T56. It can be done on a budget! If you get an LS1 t56 you can subtract $200 because you won't have to change the input shaft to use the adapter.
Also this will allow me to run lower butt gears to compliment the aluminum flywheel, double overdrives, and awesome exceleration as long as I can shift fast enough with 4.88 rear gears.