What carb

[bobfil]

I have a 72 350 with intermediate GM heads, mild cam, Edelbrock alum proformer manifold, and holley (4175) 650 carb . This carb has given me problems, won"t idle from start to next stop, idle is different any where from 500 rpm to 1200 but gets better as you run. Any suggestions on new carb, 650 probably too much, 600 better choice had enough of finicky holley, thanks Bob.

 

[duke94]

Tough to beat a good Qjet. If you can't find one, the Edelbrock carbs work well.

 

[minifridge1138]

The problem with idle sounds like a choke problem. If the choke is opening slowly, then you'll stay on the fast idle circuit too long and have a high idle.

Quadrajets are supposed to be very good carbs. Holley or Edelbrock (I can't remember which) makes a reproduction Quad that is identical to the originals.
Small primaries provide good fuel economy during cruising.
Large secondaries provide good accelration during heavy pedal.

600 cfm is plenty for a 350.
A 607 cfm carburetor will get a 350 c.i.d. engine operating at 100% volumetric efficiency to 6000 RPM.

Typically, naturally-aspirated motors run below 100% VE (closer to 85%) and i don't know if you want to rev past 6000 RPM.

 

[Tom73]

Tough to beat a good Qjet. If you can't find one, the Edelbrock carbs work well.

Got to agree, the Q-Jet is hard to beat as a street carb. By the way it has the capability to flow 750 CFM but only if your car can use it.

tom...

 

[Vettehead Mikey]

Any suggestions on new carb, 650 probably too much,

Stock carb is 750 cfm.