Guys, I have a 69 Z/28 with a ZZ3 350 running a 750 Holley. I rejetted down from 75-65 primarys and leaned it out to 1/2 a turn. I added NOS Octane additive with about 1/2 tank of gas. I passed everything with flying colors except the Idle Hydrocarbons. Reading was 505 max 450. My CO at idle was .7 max 5.0. Any quick fixes. AZ really needs to get their head out of their butt on collector cars!!
Thanks, Dennis

 

getto rig as many cats as you can in the exaust?
put the iron manifolds back on?
cover over a hole on the carb and jet it even lower?

 

High HCs are usually the result of a dirty engine or running rich. I failed the NJ test (much tougher than yours) due to an exhaust leak and a bad fuel injector. Look for exhaust leaks or check for a rich condition.

 

you have emission checks on a 69 camaro??? Thats retarded!!

 

You need to fool around with the timing and idle adjustment screw. I had a 68 Camaro SS396 that was built up big time and we were able to get it to pass NJ emissions. It was pretty much impossible to drive, but it would sit there and idle and pass emissions. After passing, I had to readjust the timing and carb all over again.

 

I'd say that people who run their cars so rich that there's a black cloud behind them need to get their heads out of their butts.

Seriously, though, put the thing on a sniffer, and figure out your idle and run A/F. Jet the primaries to stay close to stoich (14.7:1) and you'll be fine. You'll also likely be amazed at your improved gas mileage.

If you're already too lean (not what you think, but what the machine shows you- I find that nearly EVERYONE runs their carb too rich, particularly Holleys), pull the timing back about 5 degrees and run the test again. Over-advanced timing will increase HC as well. In fact, with low CO, I'm guessing that's what it might be.

Todd