Fuel Problem... maybe?

ok. i have asked alot of dumb people around town and get a different responce from every one of them. hopefully i can get a good responce from you guys, since its been proven time and time again alot of you are technical geniouses. anywho, ok here is my car first: 1984 350ci camaro; engine swap bored .30 over, .454/.454 268h comp cam, accel distributor, b&m shifter + kit, 750cfm holley 4160carb, weiand high rise manifold, headers, custom exhaust. everything else to the best of my knowledge at the time is stock. ok, when i drive around casually virtually no problem, however the second i open the secondaries for any reason it misses. i can run it up to 6k+ no problem slowely, but if i mash it at 1k it misses. fact: only when carb vacuum secondaries open at any rpm. any help would be very appreciated, i have been stuck with this problem for literally a year (wasnt doing well on the monetary spectrum until recently)

You are running too much carb for that engine.
"How To Calculate CFM:
Engine size (CID) x maximum RPM / 3456 = CFM
CFM @ 100% volumetric efficiency

(Example: 350 CID x 6000 RPM = 2,100,000 / 3456 = 608 CFM)

Approximately 608 CFM would be required for this engine. However, most Street engines are capable of achieving only about 80% VE; a modified street engine with ported heads, headers, intake and carburetor can achieve about 85% VE; a fully modified race engine can achieve 95% or greater VE. The CFM number arrived at with this formula must be factored by this percentage. "

Try using smaller jets and see if that helps.

ill give it a try. i thought horsepower also had a step in cfm. also, any head recommendations *fully assembled* for about 10:1 comp ratio? im trying to make a 400hp weekend fun machine. also, with 218degrees cam duration set to achieve peak horsepower at 6250rpm, what type of manifold should i use? thanks for all the help btw :) i ordered a set of 40 different jets from holley along with a kit to allow the carb to quick install new jets for both the primaries and the secondaries.

i ordered a set of 40 different jets from holley along with a kit to allow the carb to quick install new jets for both the primaries and the secondaries.
Very good thinking.
Heads will yield you the most HP gains if you are running stock factory irons now. TrickFlow or AFR would be my choice, especially if you do hit the 10:1 CR. 64cc heads.

A single plane manifold should do just fine.

I never asked..is that Holley a double pumper? If it is then you have WAY too much carb for that engine.

218 duration isn't a whole lot, might want to look into about a 224...with around .500" lift

i was looking into harland sharp 1.65:1 ratio rockers which would take the cam to .5/.5 if my calculations are correct. i dont believe that raises duration though, would that suffice or should i still go and get a slightly larger cam? its not a double pumper, 4160 4 barrel 750cfm holley vacuum secondaries. should i go like performer rpm, or victor jr?

If this is to be a street driven/daily driver, stay away from alumnium roller rockers, they are not made to last 100k miles and won't net you any HP gains. If you want any kind of roller, get the steel roller tip rockers.
On DeskTop Dyno it shows 385 HP at 5K RPM with 1.6 rockers and 379HP at 5K RPM with the 1.5 rockers. This is using Trick Flow heads.