Small block help

you'll need at least an 8-1/4, or better yet an 8-3/4" rear axle. That 7-1/4" will not last long behind a healthy 360, especially if you plan on spinning tires.
Not a big fan of quadrajet, but they're ok. If you need another carb, I'd look for an early Carter ThermoQuad. They can be had for less than $50 often times. If the police pkg engine is really a 79, it should have come with a TQ, originally. I am a little biased, I guess, because I've rebuilt maybe a 100 of them. Some people opt for an edelbrock afb copy, they're available new, meh, they're ok, I guess.