467-Ratman

Took the Holley 850DP off the car, and sure enough the throttle plates where not the same. The front plates have a small hole drilled in them and there is just a small amount the transition slot showing. Now on to the back plates, no transition slot showing at all and no holes drilled. Should both be the same? The car was running very rich before and I want to see if it can be leaned out some.......

The Dude

The holes in the primaty throttle plates were more than likely put there by a previous owner/tuner to accomplsh just what you desire--let more air in at idle to lean it out. (Maybe the factory does this, too, since it is a mod that Holley recommends when you're idling REALLY rich and can't lean it properly with just the mixture screws. I dunno.)

Part and parcel of this mod is to adjust the secondary throttle plate so it, too, lets more air in at idle. This is accomplished by turning a small adjustment screw located on the passenger side underneath the throttle plate. You can't miss it.

To make this screw and its adjustment easier to work with, I simply invert the little screw in its threaded hole so that the slot for your screwdriver protrudes at the top instead of underneath.

Sounds like it's all set up for you--you just have to work with it. Good luck.

Brettmc

This cannot be done. At least on my 850 DP it was impossible. I bought a secondary idle adjuster from Holley. It fits in the same place but it has a different type screw that points up, allowing you to adjust it from the top. Ratman, I'll send you this adjuster for FREE!! On some conditions tho...you have to keep your 850, ditch the for sale ad in the parts section, and never utter the words quadrajet again. :lol: :lol:

Also, you need to put the wires back in the idle passages in the metering blocks. Do a search on this. I had a thread that someone put a pic in that showed exactly where to put them. If you can't find it, email me and I might be able to scrounge it up.

Brett :thumbs:


[Modified by Brettmc, 7:58 AM 5/7/2004]

467-Ratman

Brettmc, Thanks for the advice on the carb! Looks pretty simple to me to adjust the secondary throttle plates, and as I saw in a previous post the transition slots should be the same size front and back. Should I drill the back plates to match the fronts? My front plates have approx. 1/16 holes. And now over to parts for sale section to take it off the market!!!!