i'm tdy right now and that's usually when i have all  the time i need to work on my daily driver, which is an 84 Monte Carlo SS. well as you all know the stock 305 isn't the best mouse to be motoring around in and i'm working on a 327 to drop in its place. but for now i have a edelbrock performer intake manifold and a holley 600 cfm carb i'de like to install on the 305 as long as i'll have the hood clearance. what i'm wondering is what would the expected gains in hp&tq be? if you are wondering why i'm even bothering to do so, it's because i'm working with an army budget and i've got some left over engine dress up kit parts,(valve covers, air cleaner, ect..), also it will be a while before i can finish this 327. hopefully before i deploy again. also i'm wondering if the cars computer control system will work funky in dealing with the ditributor or not since i'm swaping the Q-jet for a holley. will i permanently have the check engine lught on? also i'm not running any of the emissions equipment other than the cat/converter because the smog pump froze up on me. please let me know if i'm making a mistake or not with the manifold/carb swap, or if you have any advise or suggestions i'de greatly appreciate it.  

So,youre planning to put too much carb on a stock 305 with an already badly  restrictive exhaust.Youll probably have losses rather than gains with overall drivability.A 600 should b on a modified 305,at the least.Youll need it jetted down a bunch on a stocker.Even then I think youll find its a lot of carb.As far as gains,Edelbrock claims 7-10 hp& 14 lbs as I recall with there 600cfm&performer man. on a WELL tuned stock "350".Good luck with the thing!