I'm not a 3rd gen guy, so I'm a little out of my element here. I'm inquiring for my brother, who has an '86 Z28 with the 305. The car just had the intake manifold gasket go out on it, so my brother wants to do some upgrading. He's not nearly as experienced/knowledgeable with cars as my dad and I are, and he's more of a shoot first then ask questions person. I want to give him solid advice, but I don't know carbureted stuff, or 3rd gens for that matter.

He wants to get a upgraded carburetor (he's thinking Edelbrock) and a new intake manifold to go with it. This car is his daily driver, so it's 100% street driven. He just wants boost in power/performance while maintaining driveability. He also wants a setup he won't have to mess with--tune it once and don't worry about it for a long time.

Any thoughts/suggestions on which carbs/intakes he should look for is appreciated.

 

And before anybody says it, my brother isn't getting a 350 lol

 

Edelbrock is the easiest to tune, a electric choke would be nice too....keep the stock manifold. Upgrading it on a stock 305 won't be worth the results..well you won't get a boost in performance sorta speak.

 

First question would be is the emissions system in tack and does it need to stay that way? If so don’t mess with it as your brothers car has a computer controlled carburetor and distributer.

 

Emissions system is in tact, the car is completely bone stock. Not sure about if it needs to "stay that way." He lives in Florida (stationed there for the Air Force), but it's registered in Wisconsin, and I know Wisconsin doesn't have any emissions inspections. He keeps saying that he wants to delete the emissions stuff, but I'm quite confident he doesn't have a clue about what that will all entail.

 

Well to change the carb he has to disable the ECU- replace the distributer and Carb. He can get a little more out of the mid range RPMs the torque style intake. This would have little or no effect on Max HP like everyone likes to brag about but it would make the car slightly faster in the ¼ mile and it will show up on a butt dyno.

Setting up a Carb and distributer on an engine is easy getting them right all through the RPMs takes a lot of years to learn how to do. Even then for the car to just match the performance of computer controlled you are going to have to run premium gas and still will not hit your current mileage. The knock sensor allows the factory to run more timing advance because the system can hear the spark knock and reduce timing as needed.

Of course this all assumes the computer is intact and working right. The reality is, if you not upgrading the Cam and heads removing the computer is going to hurt the cars performance and MPG and will cost a lot if you do it right.

 

Did/Does Edelbrock or Holley make a Quadra-Jet carburetor that's a direct replacement for the OEM Quadra-Jet?

 

The answer is yes, Holley makes a spreadbore carb that replaces the quadrajet. And to Gorn's point about having to replace the carb, distributor, and computer....no, you don't. You can replace only the carb, and leave the computer controlled distributor alone. All that will happen is the computer won't be metering the carb any more, but the rest will work the same. Also, what transmission does he have, an automatic with a locking torque converter perhaps? That's another reason why he doesn't want to remove the computer. But, if your brother plans on still keeping the car somewhat stock, I don't see the point, and probably no gain, in replacing his Quadrajet with a non computer controlled one. He needs to figure exactly what he wants to end up with, and work backwards from there. By "delete the emissions stuff", does he want to rip out everything and make it old school? Once you start talking about a cam, headers, and an aftermarket intake, then performance wise he's going to want a different carb. And although not a necessity, an aftermarket distributor allows one to tune the engine the way they want it. Then there's the question of what are his mechanical skills? Can he tune a carb and a distributor without opening a big can of worms and make things worse than he has it now? His car was designed to have a balance of (cough) performance and gas mileage. It's not set up for ultimate performance, because with that can come a cost of lower gas mileage.

 

When you say still works you mean the car will run but it will not work as intended. The spark mapping assumes the carb is adjusting to the same sensor inputs it is seeing and adjusting the fuel mixture. Effectively the car is tuned to a carb that can react. Obviously once you remove the computer control carb the O2 sensor become useless. Once the computer cannot control the fuel ratio you are going to get a Lean/rich code check engine lite. That will hurt the motor function way more than putting a different carb to possible help. The truth is the stock 305 4 barrel is over carbureted to start with. I would bet I could switch that over to a 2 barrel and you would see very little change below 4500 RPMs. If you remove any other sensor the computer the ECU will lock in LHM and not adjust the timing base on any sensor input and just follow a predefine map.

When you look at what the “chips” or aftermarket Proms on the CCC systems use to do to gain more power, they played with the spark mapping and spark knock sensitivity. They required 92 octane to run right.

 

Just leave the old carb plugged in and hang it on the firewall, and the computer won't be any the wiser.
Seriously though, unless I'm mistaken, I thought there was a way to fool the computer into thinking it's still talking to a cc carb?