Slant no 1 was killed by extreme abuse when I was 20. Over revving, neutral dropping, down shifting (in lieu of no brakes). I suspect it was helped by the nice person (my girlfriend was seeing) who pour some type of crud in my fuel. I kept it going, but then a screw fell from the 1bbl into the engine. Rebuilt the top end and put a cam in it. My dad fabbed up a 4bbl adapter to a 2bbl intake. Blew the 7 1/4 rear, blew a 2nd 7 1/4 and then an open 8 3/4 (bad build) led to a ford 9 inch for 50 bucks (This was 25 years ago) Put a posi trac in the 9 inch, but it was a 4:88 ring & pinion (good junk yard find). Ran like that until I overtemped it and it seized. I took another 225 out of my sister's 77 aspen SE coupe (after she bent the car in half for the 3rd time). Bolted it in, new cam, 4bbl and mustang kill'n came easy. About 7 months later, I'm walking and taking the bus. What I learned- a 4:88 rear is not meant for daily driving, Overdrive is a needed function- not just for fuel economy, a cooling system is very important, at least a good functioning one. Oh and I now fully believe in tachometers.