460 build help!

alright i have a 1970 fastback mustang. here are my options, i got a complete 85 460 completely stock, i also have 70's 429. my question is what should i go with? im wanting a high compression motor (10.5:1) with a automatic. im shooting for 500hp. if i go with the 460 should i put the 429 heads on it? what pistons are best (and cheap) let me know what i should get.

which heads to use?
Cam?
Intake?
Pistons?



Thanks Jake

The 70's saw lots of changes in the 429/460 heads. Can you get the numbers off the block and heads of both engines? That would help!!

Bill