I'm putting a quadrajet on my 79 and need a little help.

The fuel level in the bowl is getting too high and is soaking through the airhorn gasket. What could cause this?

The fuel line registers 7 psi. The carb is freshly re-built and has a new needle and seat and float. It runs really good until fuel starts to soak through and seep into the throttle bores.

 

Sounds like either the float is set way too high or something is holding the needle valve open. I had that happen once when something got caught in the valve seat.

 

You might check with a good quadrabog shop, but I think 7 psi is too much for the stock needle and seat. Try regulating it down to around 5 and see what happens. 6-7 is usually good for a Holley, and the Quadrabogs need a little less.
Your float may have creeped up a little also, wouldn't hurt to take 'er down and recheck it.

 

I wondered if that pressure was a little high. The carb is a re-built by Holley. I figured that the float setting should be Ok, but I guess I should check it. If I put a regulator on a stock type fuel pump, is it likely to starve for fuel on the top end?

Thanks for the help

 

get ride of the quadrajunk and go for a holley, demon, or edelbrock/carter afb.

 

As long as the regulator holds a steady pressure, and the pump is up to the task, it shouldn't be any problem. Does it run ok at higher RPMS now?
Flow volume and pressure are two seperate things; as long as the regulator doesn't restrict the flow down to a 1/8" hole, you should be fine.

 

The old Q-Jets floats were fiber type that will soak up fuel and have to be replaced with a new one. If you are not sure if it is a new float, I'd buy a new one once the top is off. The float level can be set buy setting the top of the float paralell with the top of the bowl. Not even with it but paralell to it. Also check for trash in the seat first of course. Later>>>>>>>>

 

Z-attitude got it exactly right.

 

That sounds good. I'll have a new float handy before I get inside the carb.

I have not had a chance to run the car much since I put it on. The throttle response is way better on the low end than it was with the Holley. Once I get the pressure problem under control, I'll work on tuning the secondary side for top end. It feels like the air valve needs to be loosened up and might need the rods and hanger looked at.

I'm switching to the q-jet from a Holley 650dp. The Holley works pretty well wide open but I cant get any consistancy out of it for regular driving. I have always had good luck with q-jets, so I thought I'd give one a try on this car, too.

Thanks again for all the help.

 

My motor is bored out 60 thou and flat top pistons 10 2 1 comp 501 lift cam 202 valves 373 posi 4 speed t 10 I run a q jet it works awsome top and bottom end I like holleys but your allways ajusting them good luck with your carb

 

I've got a regulator that I can use that came from another vehicle. I'm not sure if it just chokes the line down or has some other method to regulate. If I have to use a regulator, I'll make sure it doesn't reduce flow as well as pressure.

I'm going to try and check the float this weekend and also re-check the unregulated pressure. Before I switched carbs, the motor would pull strong to 6k or so without a problem, so I think that the pump can handle the load.