I took my 81 Z28 to a local friend/mechanic to have a small fuel leak and timing adjusted. He fixed the fuel leak and set the timing to 8degrees he said. After talking with him he thinks that my carburetor is way too big. I just had my motor rebuilt, its a 350 with an Edlebrock top end kit the profermorer RPM series rated around 410hp. I was told by the engine builder that i needed a way bigger carburetor for my set up (i know nothing about carbs) . So i was told to purchase a 850cfm, so thats what i did, i purchased a Holley 850cfm with all the goodies electric choke and what not. Is my Carb really too big? My friend said he thought it was running rich and tried to adjust it i believe. I've only talked to him on the phone i still need to go pick the car up.

Also, it has touble starting after sitting for a couple of day, my friend adjusted the timing and tightned the choke so hopefully that will sove this problem.

 

That's prolly way too much carb for a 350. Just my opinion...you might be able to jet it down, I'm no carb expert, but that sounds like too much for a mildly built 350.

 

On top of the overly rich condition the larger venturi on the 850 are probably slowing the air entering the engine down. This could lead to less power and torque all by itself. I'm guessing that the Eddy kit has a 750 for a reason. Your builder sounds like a tart. No offense to you. Edelbrock has done so much R and D on that kit that it is pretty much as dialed in as its gonna get. Do you have the heads too? If you have the heads I'd bet my paycheck on a 750, if its just intake and cam then I'd go 650 maybe even 600 depending on max rpm and the heads that are on it. I dug this up for james and figured you might want it too. http://www.bob2000.com/carb.htm the way he goes about tuning is great and the home made A/F gauge is the one sweet.

 

The edelbrock kit that i bought came with head, cam, intake. It did not come with a carb. So is it not a good idea to have this carb set up on my car, is it going to kill my motor?

Another issue that my friend found was that our brakes run off engine vacuum. Well, since my cam is so big my car doesn't make much vacuum pressure, therefore my brakes don't work nearly as well. Is there a way to fix this?

 

As for the brakes,there are a few options.You can get a vacum reserve canister from jegs or summit,they also sell an electric vacum pump that you can hook to your brake booster so there is always vacum going to the brakes,or for alot more money you can get a hydroboost brake setup that runs off the power steering instead of engine vacum.Here are a few links for examples of the first 2 that i mentioned.
http://www.summitracing.com/parts/CCA-5200/
http://www.summitracing.com/parts/SUM-760151/

 

The 850 wont "kill" your engine, but you'll make way better low end power and mileage with a 650 or 750. Just way too big! I'm running a 750 on my 427 bored to around 440 ci. and it works great. I wouldn't think of running an 850 on my engine, even with a lot more cubic inches.