This is my first post so please be gentle:)

First of all, thanks to all the very knowledgable people that post here and have already indirectly anwered many of my questions.

I have a 68 convert that I recently bought from my father-in-law. For him the car was more of a drag/race car but I want to use it more as a daily driver. This brings me to my question.

The car has a zz4 with a 650 Holley Street Avenger carb, the GM "Hot Cam" kit (1.6 rollers, .535/.525 lift 210/228 duration 112 LSA), and a 8.2 10 bolt rear end with 4.10 gears.

The two issues I have which are affecting the streetability of the car are that it failed emissions and the electric vacuum pump is giving me problems.

I may be able to pass emissions by adjusting the carburator since it only failed the idle test, and I could continue to deal with the pump, but I am considering changing the cam to get more vacuum and improve emisions at the expense of power.

If I go back to the stock zz4 cam (1.5 roller, .474/.501 lift and 208/221 duration 112 LSA) will that solve the vacuum and emmissions issue?

Any other suggestions?

Thanks,
Justin Allen

I guess I would not have thought a 210 intake duration at .050" cam would give you any vacuum problems??

What's it's advertised duration?? I ask b/c I'm not up on the newer cams at all..

And yes, smog tune the idle settings..

pdq67

The Hot cam has 219* intake duration at .050, 228 exhaust.

Mine pulled 15" vac @ 800ish idle....no problem at all with vac brakes. You shouldn't need a vac pump with it.

Sounds like you might have a vac leak somewhere and/or need to tune the carb a bit.

http://img.photobucket.com/albums/v61/gort69/hotcamcard.jpg

Thanks for the replies and for posting the cam card, I could not find it online. I will check for vacuum leaks and see about adjusting the carb and measure how much vacuum it is making. I'll be very happy if I can keep the cam.

Justin

Thanks for all the help. I have been doing some trouble shooting, but it looks like this is a brake problem so I will let this thread end and post my brake related problems in the brake forum.

Thanks,
Justin

A properly tuned idle mixture will build vacuum as well. Turn the mixture screws a little lean(within reason) for the emissions exam, but afterwards, tune them with a vacuum guage for best vacuum. Whats initial timing as well? Disconnect the vac advance and plug its port on the carb and have a look see. At least youd want 8 degrees initial timing(with the vac unhooked), and try more of course in 2 degree increments. So, try out 8 degrees and see how it works, than try 10, than try 12........

The Arizona governor just signed a bill into law last month that exempts our old classic cars from emissions testing; when does it go into effect?

John,

Look in your State's "Air Program's" site on the "Rules in Progress" site and that should tell you??

But usually, they quit checking them b/c the Air Pollution Control Program's Air Commission or whoever grants a variance after the Gov. sign's an exemption! And it is sometimes like a year and as long as 16 months for the Rule to catch up!

I'm in that situation now b/c I have our State Rule 10 CSR 10-5.380, Motor Vehicle Emissions, for the St. Louis Nonattainment Area to amend and the timeline is 16 months! The Missouri Air Conservation Commision granted a 12 month variance and so we will have to go back and ask for an extension while the rule catches up.

Right in the thick of this stuff at work at MoDNR/APCP as an Environmental Engineer Air Rule writer.

pdq67

In NJ, 25 years + older are exempt if they have historic plates, which legally limits driving (shows, repairs, etc.). If AZ has that, the words Daily Driver could cause you inconvenience.

It looks like the law is now awaiting EPA approval which could take 1 or 2 years. It also only applies to "collector cars" that carry collector car insurance. I am not sure what that is, I carry regular insurance on my car. I believe there are mileage restrictions on collector car insurance. It is still good news for many hot rodders though.

-Justin