got a 1984 HO V8 was given a holley 600 cfm carb numbers are rubbed out but its a single pump with an electric choke. Anything i need to know before throwing it on. the carb was on an 86 z28 before i got it

Yeah, it won't bolt onto a stock intake manifold. Your original cc-QJet is spreadbore and the Holley is squarebore. Not just the bolt pattern difference, but if you remove the QJet you'll see 4 holes under the carb on the intake's carb pad that only match up with a QJet's big-n-little throttle bores. Aftermarket intake is called for if you want to use the Holley. Plus you'll need to swap out the computer controlled HEI distributor for an earlier non-computer controlled one. If you take the carb off the computer you have to take the distributor off as well (and vice versa).

NOT!!!.......You could just spend $10 on a spreadbore to squarebore adaptor (or try to eBay a squarebore intake but the shipping BLOWS)....adaptors do slightly impead intake velocity and efficientcy but its cheaper than buying a $100 plus intake......and like the OP said the #s are rubbed out on the carb....Holley did make spreadbore carbs, he might have one, unlikely but possible......but you are correct in the fact that he'll need a new vaccuum/mechanical advance Distributor( or do the Five7 mod), because the stock one on an 84 has an electrical advance....

thanks alot any suggestions as to what distributor works best

Red- I'm aware of spreadbore/sqarebore adapters but I'd advise against using one on the stock intake. The stock intake is a pretty lousy intake to start with and you're adding another restriction point on top of that, plus the possibility of mixture distribution problems.

Damon - sorry bout the Wanes World moment earlier, but it seems like we do agree on the facts anyway.....I just saw the word NEED and thought it should be clarified and I did....However childishly....but back OT, if a guy had it on an 86 Z28 before he got it, he probobly has all the means to install it on his 84 anyway, wheather it be an intake or adaptor or W/e.....so now he can just pick up a new vac/mech advance dist from AutoZone or Advance for about $100 (Accel or MSD are good brands) or go the eBay or junkyards route looking for pre - 81 Chevy Dist.