What chevman describes and Cosmo concurs-with is the best technique to consider when installing the SM420. It cost is minimal (cheap bolts work fine) and you can cut the heads off in a few minutes.
As you slide in the transmission, can easily rotate the output shaft/yoke on the transmission to align the splines on the front shaft to the splines on the clutch plate.
Be sure to check the fit of nose on the transmission's front-shaft with the pilot bushing (before installing the pilot bushing).
