So you want 2 go Big block...Read this first!

Where to start..Well if your running a SB to compare output to a bb yes you will want an aluminum radiator and yes you will want disc...and subframe connectors...I just bought a running 230 casting 400 with working tranny for $250...depending on what you start with you will probably need an *3/4 with the driveshaft shortened....and yes I have done several BB swaps in a-bodies from a 70 duster with a 383 to a 70 dart with a 440 that ran 11.65 on street tires and pump gas.So i think you are tryin to compinsate but I wasn't starting anything yet i was just pointing out my opinion....O yeah and I have also went SB also...
P.S i spent $250 including shipping on an 8 3/4 but i went B body for the extra width...also i looks like you have a few PROBS in your description.?