Q-jet and Holley

Alan Roehrich · 12-21-2011, 03:56 PM

Quote:

Originally Posted by vic guilmino

i removed a 780 holley and
i put a q-jet on my 429 ford
same mph but et was .2 slower
carb when very rich in the first 100'
need help with that

Vic, does your carburetor have the little air deflector on the top behind the choke horn? Often you find that the combination of a slightly high float level and that little sheet metal deflector not being there will allow fuel to splash out of the bowl vent and into the secondaries.

If you do not have it, the best book for the Q-Jet racers may possibly be the book Doug Roe wrote, it's available from HP Books.

http://www.amazon.com/Rochester-Carb...4497285&sr=1-2

Ed Wright · 12-21-2011, 08:38 PM

The two holes above the rear upper throttle blades may need restricted. On larger engines they can often be plugged. They act similar to an accelerator pump for the secondaries. Might try tape over those holes for a pass to see how it acts. If it stumbles with them plugged, you may need to restrict them.

Adger Smith · 12-22-2011, 08:54 AM

I have used toothpicks in the holes.

12-21-2011, 08:38 PM	#2
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	Re: Q-jet and Holley The two holes above the rear upper throttle blades may need restricted. On larger engines they can often be plugged. They act similar to an accelerator pump for the secondaries. Might try tape over those holes for a pass to see how it acts. If it stumbles with them plugged, you may need to restrict them. __________________ Ed Wright 4156 SS/JA

12-22-2011, 08:54 AM	#3
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: Q-jet and Holley I have used toothpicks in the holes. __________________ Adger Smith (Former SS)