Carb help

by dcrews Tue Feb 16, 2010 11:30 pm

Ok guys. I need a little advice.

74 Grand Am, 400 2bbl.
I'm changing to an edelbrock performer intake, putting headers and dual 2 1/2's on it.
I've decided on an Edelbrock carb, but am torn between the 600 and 750.

It has the stock cam for now, but I plan on upgrading to a bigger cam, something along the lines of a comp cams 260h or 252h.

Ok, any ideas?

by dcrews Wed Feb 17, 2010 12:16 am

Or maybe a good old 3310 holley? Aren't the holley vacuum secondary carbs supposed to be able to compensate for an engine being over-carbed?

by ant7377 Wed Feb 17, 2010 12:42 am

Why not just rebuild the Quadrajet? Most are good for a 750 CFM and i bet on
a 400 that one is.

by dcrews Wed Feb 17, 2010 12:43 am

No qjet.. It's a stock 2bbl

by dcrews Wed Feb 17, 2010 12:44 am

I wish I had a good qjet for it, I'd use it. But they're stupid hard to find around here, and I'm not sure I could rebuild it if I had t here anyway.

by G3NUT Wed Feb 17, 2010 12:56 am

Go with the edelbrock 750 they are the best bolt and go carb.
And if you find that it runs to fat on the stock 400 then you can just change the metering rods and jets.

by Roadcaptain S3 Wed Feb 17, 2010 8:52 am

I pulled the Q-Jet in favor of the 600 Eddy, Q-Jet was a 750 and needed rebuilding. Went with the 600 cause I will be driving a lot, so I comprimised between power and fuel economy, Kinda get a little of both with the 600. plus I have the Eddy RPM intake.

by ratnfested Wed Feb 17, 2010 9:08 am

I'm partial to Demon carbs. Most Holley parts fit and they are easy to work on.

by The Dude Wed Feb 17, 2010 12:25 pm

Edelbrock or Carter for me. Easiest to work on, don't have to worry about blowing out power valves, better gas mileage & throttle response (debatable but I think so). 600 is too small for a 400 IMO. Try a 750 & jet down like G3NUT said.

by dcrews Wed Feb 17, 2010 2:13 pm

k.. 750 it is Smile

What do you guys think about the national carburetors rebuilt qjets?

by Limey SE Wed Feb 17, 2010 2:17 pm

if you wanna have the quadrajet I have a spare one here prob needs rebuild so would sell it as a core

by dcrews Wed Feb 17, 2010 2:24 pm

I'm just not confident about rebuilding it myself.. I've never done a qjet before. I've done edelbrocks and holleys, but I hear the qjets are a totaly different animal.

by Limey SE Wed Feb 17, 2010 2:24 pm

very different that why it has sat for as long as it has, prob better part of 4 years

by dcrews Wed Feb 17, 2010 2:35 pm

I work for a major auto parts store, so I can get a 1406 or 1411 for around $240 or a 3310 for around $210

just want to make sure if I get a 1411 (750cfm) that it won't drown out my poor tiny little cam

by Limey SE Wed Feb 17, 2010 2:47 pm

O i would only sell you the QJET for 60 bucks so way ahead of the game on that one I want it to go to someone that will actually use it

by 74Malibu383 Wed Feb 17, 2010 6:48 pm

The Holley Street Avengers are pretty awesome. Much easier to use/tune than the older Holleys.

by bigredlaguna Thu Feb 18, 2010 2:50 am

On a Q-jet, the main things you need to pay attention to are:

1) Float level

2) Epoxy the plugs on the bottom of the main body casting to prevent the fuel from leaking.

3) Make sure the secondary air valve spring is set properly. This is the cause of most "Quadra-bog" complaints. It is a sensitive adjustment but at least it is relatively easy to adjust even when on the engine.

4) Have the throttle blade shafts checked and re-bushed if they are out of tolerance.

On a stock or close to stock engine you will be hard pressed to beat a Q-jet.

by dcrews Thu Feb 18, 2010 8:36 am

I took the plunge and ordered a reman q-jet..

We'll see how it works out Smile

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