Intakes are limited to basically a Weiland aftermarket one for 600+ or a factory 4 barrel, 6 pack or , dual quad, all of which can run from 350-900.
the poly heads will out perform any LA head, stock for stock even more so with porting and polishing.
Headers are essentially limited to TTIs, or you can custom modify a set from a Mustang GT or 351 to fit.
you can also modify an LS intake to fit as well, both are easy to do.
cams can be custom ground for under 200.
I’ll get into more specifics in a later post. Busy at the moment but gives you a few things to think over