John1963

Can anyone recommend a modern carb for my F85 4bbl?

Someone replaced the orginal 4GC with a Rochester 4jet that is too big for the car.

Thanks,

rocketraider

A 4GC, a 4Jet and a MultiJet are essentially the same carb, all rated 450-500 cfm range. Why do you think it's too much carb?

oldcutlass

x2?^^^^^^

MDchanic

Yes, 4GC is just the letter designation for the carb named the 4-Jet, just like 4MV is the letter designation for the carb named the QuadraJet.

- Eric

455man

I thought I'd read somewhere that they were up to 750 CFM depending on how much CFM the motor needed? Wrong carb?

rocketraider

You're thinking QuadraJet. That was part of the magic of them, was that they delivered the cfm the engine wanted up to its 750-800 cfm limits.

4GC are limited by smaller equal-size throttle bores and a comparatively small secondary air valve.

Back to OP's question, the only other real option you have would be a small squarebore Holley, say 450-500 cfm rating or so, and then you'd have the aggravation of setting up your transmission throttle valve rod to work with it and keep your baby SlimJim functioning. If car is a stick shift, you should have no issues putting the Holley on it.

There are several guys who are good with the 4GC and can set it up properly for your 215. You may have a big car carb which would have larger jets than the 215 needs. That's one thing that bugs me about the 4GC, is that they have a detachable aluminum tag with the carb # on it. If that tag is gone you really have no way of identifying what it is, how it's set up, or its application.

455man

Ah. Thanks.

BILL DEMMER

actually, it would be the 4G <that is the series, there were 4GV's and 4GC's. the V or C denoted the type of choke. the number denotes the quantity of barrels.

4M is the quadrajet series, but it gets a little fuzzy in later years.
4MC
4MV
M4MC
M4ME
M4MED
E4MC
E4ME
etc; etc.

and worthy of mention was the 2M/4MC dualjet-the infamous "half of a quadrajet"

anyway, back to the op's subject...
why do you think it's over-carbed?


bill

MDchanic

Absolutely true.

- Eric