Hello everybody,

I am a proud new owner of a 1967 Chevy Camaro, it has a Chevy 327 motor in it. The dealer told me it has a newer cam but does not know what type. There is no build sheet on the vehicle so knowledge is minimal. When driving the car at slow speeds there is a lot of bucking and it doesn’t like to idle much or run at slow speeds. We had it professionally tuned but it is still having similar issues of running right at idle and stalling out. The guy working on the carburetor said he doesn’t believe there is a vacuum leak but suggested the cam may be misaligned when it was installed. Vacuum at idle was around 5 which i feel is super low. Any suggestions before we tear apart the front end and check the alignment of the cam? We put the exact same carb on it to check if the carb was the issue and still had the same problems. Thank you for any help or suggestions.

 

Yea 5 inchs is way too low. It could also be the wrong cam. Most racing cams will not idle well under 1300 RPM and in some cases 1500. Low vacuum is another sign of a Cam being too radical. Most street cars with big Cams end up with vacuum pumps added so their power brakes work. It is one of the biggest mistake guys make when building a motor. They say I want the most power possible. They get the biggest Cam they can fit. Withing 8 months they are swapping cams for a more street able version.

 

Thank you so much for your reply.

 

Another question and i apologize for my ignorance, you mentioned adding a vacuum pump, is this something we can do add one?

 

What is your initial timing set at? Is the vacuum advance hooked up? If vacuum advance is hooked up, is it hooked up to ported or full-time vacuum? What RPM does it idle at? Have you sprayed carb cleaner around the base of the carb while the engine is idling? Manual or automatic transmission? Vacuum pump is for power brakes.

The engine in my '69 idles at 1,400rpm with 5" of vacuum but the cam is huge, it's 274/286 at 0.050" and 704" lift. I seriously doubt the cam in your engine is anywhere near that.

 

I would check the ignition timing
I have run a whole bunch of radical camshafts
Yes, vacuum will be lower at low RPM
5 is damn sure not enough to run right at idle or anytime
The initial timing spec of 4 degrees BTDC is okay for sea level
We add 2 degrees for every 1000 feet of elevation
My current 327 is timed at 20 degrees initial at 5200'
A good digital timing light is money well spent, same with a dwell meter if you are running points
I doubt the cam is a tooth off