My 340 in my 66 developed issues :-(

I would love to get some perspective from you guys on intake, heads and cam selection. I've been told that the exhaust manifolds flow very nice and I like the look of them in the engine bay anyway, so I'm leaning on keeping them and not doing headers.

As far as the heads, I've read up a bit on them (J heads) and they seem very nice. I am most likely going to have my machine shop go through them and if I recam it they will most likely get new springs. But again, I'd love to hear thoughts on head selection/best bang for my buck.

Intake selection is vast! I need help in this area from you guys.. First off, is there much to be gained or is the cast iron one I have good enough? I seen an edlebrock ld340 intake and another one called an assault ... So many questions..

What in trying to accomplish is a car that has snap and I'd like to be in the 12's ... Once again it has a 727 trans, 355 gears w/ a sure grip.