Well, there may be more than one way.
I did it to mine by moving the trans forward about 1/4-3/8 inch. I turned the 4 trans bolt holes into elongated slots and ground the area where the brake disk/front of the trans case is so it could move forward without hitting the chassis. When I had the trans where I wanted it, I drilled two new 1/8 inch holes through the chassis and trans flanges. Then I used a screw/locknut through those holes to keep the trans from sliding around on impact. The 4 screws holding the trans was there now to add support, but I wasn't depending on them to keep the trans from sliding backwards.
For the clutch install on the engine, I used a
HPI savage 3-shoe flywheel and teflon shoes. I had to make a little extender for the crank shaft for the outer bearing to ride on since 1/10 engines have a shorter crank.
Took me the better part of an afternoon, but I never had a clutch problem again (even with a BB kit). I was also assured that all the power the engine was making was getting to the wheels.
Here are a few pics to give you an idea. I don't have the truck anymore or I'd have taken the trans out and taken a pic so you could see the holes and grinding I did on the chassis by the front of the trans.
1/8 savage flywheel/ofna bell alignment prior to modifying the chassis:
Alignment after the mod:
The trans top and bottom:
