Dad did a tune-up; did that include replacing spark-plug wires? If so, the firing order of the wires must be in the same direction (clockwise or counter-clockwise) and sequence as the distributor rotation. Otherwise, it will run like - well, you-know-what!

Hope this helps. I've done it before on a '73 302. In fact, I got so *full of myself* at one time in my young life, I'd just rip the distributor and wires off, all at one time, and put them back on without reference to firing order on the intake. (Pride comes before the fall; I learned about clockwise and counter yah dah, yah dah that day! LOL).

PS: moderator, thanks for the catch on my attitude. I just love that ******** thing when you don't pay attention!