Changing to a Performance Carb - NJFBOA - Home of New Jersey's Camaros and Firebirds

1985transam · 05-22-2008, 10:41 AM

Well Dyno day was fun, but my cars HP was low at 149.5 for a stock engine.

ok, toying with the idea of changing the Stock Carburetor for a more Performance Oriented one that is a direct replacement.

I am looking for a Driect Bolt on without Modifying the electrontic part of my 305H LG4 Engine.

Bolt on's are a easy way that I can always revert back to Original GM. Plus the carb is not seen, so that may work for me.

Looking for some advice of this topic and recomendations. Such as, what type of gains can be expected and stuff like that.

Thanks
Rob

Pampered-Z · 05-22-2008, 11:00 AM

I don't think there is a carb to replace the electronic quad. Back in the late 80's Holley did make one elec. carb, 600CFM I think it was, but it actually wasn't any better. I had one on my my car ( 334 - 305 stroker with a mild cam and ported stock heads) and went back to the stocker, had it modified with a float assembley from a truck ( had two holes instead of 1 which allowed it to flow more fuel and larger mettering rods installed ). worked better, but we never could get the computer right. I evenutally gave up trying to build a good running 305 and went 355, of course, emmisions was an issue then....

You would be better off spending your money elsewhere, but again, the 305 is limited in how much HP it's going to make, the small bore and limited valve size is difficult to overcome.

BonzoHansen · 05-22-2008, 11:55 AM

Your choices are limited. Someone, maybe Jet, rebuild CCC Q-Jets I believe. Not sure what the benefit would be past a nice rebuild. Maybe you can change the secondary metering rods.

Maybe search thirdgen.org too.

WildBillyT · 05-22-2008, 12:13 PM

Rob,

In my opinion you should save your money. Your options with the carb would be either:

A) Buy a new one, but for the same cost you could get a running 350 to build

or

B) Buy a used one and have to tune and possibly rebuild it

If I were you I'd plan for a fresh motor with more displacement.

1985transam · 05-22-2008, 03:46 PM

Thanks for everyone input on wheather to keep the stock carb or buy a performance carb.

I will keep the original GM for now.

Thanks
Rob

JSPERFORMANCE · 05-22-2008, 10:31 PM

You will see a better improovement by changing the intake manifold and installing a good set of headers/ypipe.

JL8Jeff · 05-25-2008, 09:32 AM

I remember watching an episode of Shadetree Mechanic where they put a crate 350 in a Monte SS and did some modifications to the stock 305 electronic Q-jet to get it to work with the 350. So you might want to search around for any information related to that. But the 305 carb motor is a tough one to get much out of.

1985transam · 05-29-2008, 09:03 AM

Ok, have another option for opinion here.

What if I bought another GM 4 Barrel Quadrajet Carburetor for my car. Then have it rebuilt by a reputable Carburetor shop for better Performance ????

Unfortunately, I do not know any Carburetors shops in NJ. I could ship to any location.

I have been thinking of getting another carb as a spare. The carb on the car now is New GM purchased about 5 years ago. Not even 3K miles on it.

Any opinion on this one ???

Thanks
Rob

Tru2Chevy · 05-29-2008, 09:42 AM

Quote:

Originally Posted by 1985transam

Ok, have another option for opinion here.

What if I bought another GM 4 Barrel Quadrajet Carburetor for my car. Then have it rebuilt by a reputable Carburetor shop for better Performance ????

Unfortunately, I do not know any Carburetors shops in NJ. I could ship to any location.

I have been thinking of getting another carb as a spare. The carb on the car now is New GM purchased about 5 years ago. Not even 3K miles on it.

Any opinion on this one ???

Thanks
Rob

If you had the carb sent out to a performance shop I'm sure they could find some gains for you, but the biggest thing(s) holding that motor back (besides being a small-bore 305) are the cam and heads. You aren't going to see any big jumps in power without getting rid of (or at least modifying) the original top end.

- Justin

EchoMirage · 05-29-2008, 10:17 PM

i think youd be better off buying another car as a toy, if youre worried about keeping this one stock and original. you cant do much for increasing performance without doing major changes to the motor. find another 3rd gen beater as a start for a build.

you can try davis carb in east rutherford for carb work.