‘66 Barracuda
First of all, welcome to FABO, we’re glad to have you with us. Now, as stated above, what you want out of your car is your choice, and it may make it easier to know that the original drivetrain is ok to have, but ok to change as well. You can always keep the motor, but it is not numbered to the body in any way. In it’s place could be the above mentioned choices of small block wonder, all dressed up like your 2 bbl motor. That’s what I’m doing with mine, I had it dressed up like a Formula S because I liked the dress up kit that makes the commando motor look so nice. My car is a 2 bbl car, so I’m dressing up a 340 to look like a 2 bbl motor, using a trans from a 72 car for the comparability, and it has an 8 3/4” rear. All this car will ever need. What you decide to do with your car is your choice, but I would suggest at least a refresh of your motor, you will find some ponies from freshening it all up I’d bet!