i have a 69 mustang grande, 302 3spd, i wanna drop in something bigger and a 4spd. i have a 351w block in my basement i could build thats not in bad shape, my question is, should i build the 351w and drop it in, or should i go for a big block like a 429? and what transmission should i go with, a 4spd or a 5spd, and what make? also what can i get a 9" rear off of, my 69 is just a peg leg 8", thanks