A greater starter would be hard to imagine (they are used to spin V8s when geared down), but the solenoid starter current contacts install had one easily missed trap.
They need to be dead-flat so all their available contact area is used. If they are not-so,..then early problems arise.
The problem occurs when the nut on each post ( one for the actual starter- motor,..the other for battery input) is tightened after all the new guts are installed or at any time the starter battery-cable is removed and replaced :
The stud will turn slightly as the nut is tightened. This causes the contact inside to 'c*ck' up at one end,..and down the other, making a clean and total contact by the solenoid bridging contact impossible as each contact will be tilted in reverse to each other,,,, the spring loaded contact-ring will not accomodate this mis-alignment. This rapidly leads to premature contact wear.
The trick (which the Gregories doesn't mention) is too hold the pinion out to the length of its engagement travel (a pair of vice -grips acting as a wedge of sorts,clamped with medium pressure on the pinion-boss) so the solenoid armature/plunger can be held down to cause the contacts to self-align. Then while this is all-happening, tighten the two contact studs. Remove the plunger return-spring while doing this last bit. The plunger just pulls out.
Applies to Toyotas and no doubt some other Jap cars with Nippon-Denso starter-motors.
One remedy when removing/replacing the starter during any job on the car: Its very important when undoing and tightening the nut on the battery-lug-post, to mark it first to make sure it ends up in the right position again. A screwdriver slot filed in the post-end would fix this problem.
Jason