Best size alternator?

[bigtrav101]

So I have 3 MTX 8512-44s subwoofers. 2 are going to be running off a t1500-1bdcp and the third is going to be running of a t500-1bd. I have a T4004 for my highs and it's all going in a 1972 Cutlass Supreme. I'm trying to figure out what size alternator do I need to run this off without any issues at all. If I can get by without any extra batteries in my trunk I'd def. like to.

[8ight]

Why not buy one amp that can run all of the subs? I don't gain matching will be easy. As for the electrical doing the Big 3 and getting a 270+ amp alternator will help, along with a killer battery under the hood (think XS) you will likely experience minimal voltage drop at idle.