Every T5 swap will have details that are unique to the build, but the general rules don’t change. When bolting a T5 directly to the bell, you will try to duplicate the length of the original transmission input shaft AND front bearing retainer sleeve. See photo. When using an adapter plate, you simply duplicate the lengths of the input shaft and front bearing retainer sleeve while the adapter plate is bolted to the front of the T5. If you want to double check before cutting, measure the distance from the pilot bushing to the rear surface of the bell with a piece of coat hanger wire.
The adapter plate usually solves 2 problems (as well as solving a bolt pattern mismatch in some cases) all at once. The S10 14 spline input shaft is too long and the splines are not cut far enough along the shaft to allow proper clutch disc movement. Moving the T5 away from the engine with the adapter plate USUALLY prevents the pilot tip from binding against the rear of the crankshaft INSIDE the pilot bushing. Also, the input shaft splines have been moved back far enough to allow proper clutch disc movement.
The attached photo shows a T5 with a Jeep shaft swap side by side with a factory 3 speed (Muncie?). Since the bolt pattern is the same, I only needed to trim back the bearing retainer sleeve and a little off the Jeep shaft pilot tip to make the T5 match the 3 speed. No adapter plate used because the bolt patterns match and the Jeep shaft splines are cut long enough for proper clutch disc movement.
The last pic shows that the depth of an S10 bell and a factory 1960’s C10 cast iron bell are identical. So the location of the end of the crankshaft in an S10 four or six cylinder engine must be the reason for the longer input shaft.
