I guess by "correct for the truck" you need to define what the OP will be doing with his truck. It's a term in my opinion which can be used loosely to mean "old truck with a straight shift, 3 or 4 spd, transmission". It makes no difference what transmission is used, just the end result.
Now, with my old truck, 58 GMC, I've changed the engine using all the original drive train including clutch linkage etc. so that if someone in the future wants to change it back its easily possible. Now the OP's truck has the tb350 auto in it and most of the time all or some of the stock mounting and linkage parts are gone making going back to original harder and more expensive. I'm not a diehard restoration person like some of you guys but I do love the look of these old trucks. Sometimes you just got to do what you got to do to make a go of it just to have one of these to drive and enjoy. I'm with the OP on this as far as automatics go. I'd much rather have the straight shift behind what ever engine is in it. So maybe if someone has some of those old parts laying around lets help out a fellow bolter. If he needs it I've got the flywheel and some of the linkages he'll need and he can have them no charge. Just the way I am. Larry
