Parachutes: dead weight until ya need 'em: Then, they're priceless!
It's all a betting game. <img src="/forums/images/graemlins/kewl.gif" alt="" />

By not as strong I assume you mean, not as powerful, because I would consider the 20R more bulletproof than the 22R by virtue of it's much better duel timing chain design.

However, 20Rs didn't come in Toyota trucks in '82, so it must have been a transplanted motor, so who knows what year it is or how many miles it really has on it.

One weak point in the '82s is that cruddy L series 5 speed tranny if it has a 5 speed. If it doesn't, then the other weak point is a lack of overdrive.

Also very early model trucks like that have serious rust issues, so make sure you check for that. Especially in the frame area.

Maybe someone put a 20R head on the 22R block and kept the valve cover from the head... And just to inform, the 22R originally came with the dual row timing chain in 81-82. You can easily adapt pre 85 22R to a dual row chain by simply swapping out the oil pump drive spline to the narrower ones from any 20R and 81-82 22R's.
Jeff