Your present bell housing will not work with the SM420. The bell housing that works for the 420 Does not have the 3 bolt mounting area for the brake and clutch pedals. Hooking up to the torque tube is another problem, unless you replace the rear end and driveshaft. I am installing a T-5 transmission (using an adapter to my original bell) and rear end this winter. no more crash box for me.
Good luck, Joe
