Author Topic: 1977 Chevy 454 Quadrajet Smog Results  (Read 2682 times)

Offline thumper

  • Garage guy
  • **
  • Posts: 14
1977 Chevy 454 Quadrajet Smog Results
« on: April 24, 2012, 08:17:25 PM »
Hi Cliff and guys. Just had my BB Chevy smogged today and I passed. Learned some important things.

First, Cliff, your rebuild was spot on for my application.
Second, the test RPM of about 1475 showed C02 as 11.7%, 02 as 3.4%. The C0 was 1.78, about twice the average. HC a little higher than average also.
So I need to lean the carb with the APT adjustment screw.
My question is how many turns would you suggest?
Thanks again for a great rebuild, Thumper :)


Offline Cliff Ruggles

  • Administrator
  • Qjet Hero
  • *****
  • Posts: 5432
Re: 1977 Chevy 454 Quadrajet Smog Results
« Reply #1 on: April 26, 2012, 03:55:30 AM »
Good news!

Make very small adjustments and drive the vehicle after each change.  About 1/8th turn or so at a time. 

Despite what any testing shows, aways tune for best performance, throttle response, fuel economy, etc.....Cliff

Offline thumper

  • Garage guy
  • **
  • Posts: 14
Re: 1977 Chevy 454 Quadrajet Smog Results
« Reply #2 on: April 28, 2012, 07:45:46 AM »
  Thanks Cliff for your expertise and dedication! Thumper :)