Cliff's Quadrajet Parts and Rebuild Kits

General Category => Quadrajet Carb Talk and Tips => Topic started by: von on June 16, 2011, 02:34:56 AM

Title: APT Adjust '75 Olds Carb
Post by: von on June 16, 2011, 02:34:56 AM

What is a good baseline setting for the APT on a '75 Olds (455) Qjet? Carb #7045184. This is the original carb on a 455 Cutlass. engine is stock. This is a numbers matching carb and replacing with another isn't an option. These '75 carbs have the weird additional jet and metering rod (non-adjustable) and also the adjustable  pot on the pass side front. Carb is all stock and now has a setting of 1/2 turn up from all the way down. Ran OK but maybe could run better.

Title: Re: APT Adjust '75 Olds Carb
Post by: Cliff Ruggles on June 16, 2011, 03:37:48 AM

I've never had much success with the auxilary APT models without removing the aux power piston and metering rod and recalibrating them. 

That system isn't that great, and adding fuel from the APT feeds fuel under the jets clear across the load/speed range.  It's better to re-jet, and new metering rods, so they are very, very close, and add a tiny amount from the APT system, if/as needed.....Cliff