I don't know what gear ratio a 75 Hang 10 Dart comes with, but if it's a 2.45 gear all your listed choices will suck. I had a 72 Swinger I swapped a later A body 8 1/4 in, I neglected to notice the gear ratio till I took it for a test drive, 2.45. Even with a mild 360 swapped in (stock 79 360 with 340 cam, 600 cfm AFB, stock 4bbl intake) it was a slug off the line, but at about 70mph look out.
Before you decide anything, what is your rear gear ratio?
They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.
