[84LX89GT]

I agree with Dark_5.0, there's no real reason to have a 750 double pumper on your engine, you'll get better idle, way better throttle response and low-mid range power with a smaller carb like a 600cfm or maybe even 650 if you improve the heads and get a bigger camshaft and gears.
I've heard really good things about the edelbrock performer intake and i've also heard that the performer RPM, although suited for higher RPM (still a dual plane intake) has pretty much the same powerband as the performer, but more high end power.
I've also heard that the weiand Stealth intake is a really good intake that responds well even as you improve airflow in other areas of the engine. I personally would get an the edelbrock performer intake manifold and gasket match port it and the heads to the gasket you'll be using.
Since you're in the engine anyway, why not swap out the old cam and put in a new camshaft. If you can afford it, a roller cam conversion will increase power just because of the roller lifters (less friction) and the ramp of the cam is steeper so more duration can be used with less vacuum loss.
Good luck,