Well today I got my vette out from storage and thought I might try the vaccum timing method. I bought a vacuum gauge from the zone and plugged it in to the carb and blocked all the other hoses. At 800 rpm it was reading 14 so I moved the distributor until I got a peak of 18 lbs. I locked it down and went for a test drive. Wow! Is all I can say! The Vette feels like I gained 50 hp. I have a hard time not squeeling the tires at lights now! The dyno shop didn't even get it to feel this good. Thanks for the tip Ben!

you're welcome tom.. 

my grandfather taught me that method..  he was "old school"

for curiousity what does your light say..

Heh I didnt even use a light to look to see where its at. but I'll put the light on it tomorrow if I can dig it out of my box.

cthulhu

Hooked up the vac guage to the line running between the carb and the distributor.  Turned distributor to peak vacume (went from 10 to 17).   Car idled higher so I turned it back down to 800 rpm with idle screw.  Car did not run well when I accelerated - rough.  What did I do wrong?  I read your comment about replacing distributor springs.  Do I even have those in a transistorized ignition (71 LT1)?

Thanks for any suggestions

Rgds Neil

 

 

 

You don't want the vacuum line from to the distributor.  You want a manifold vacuum.

And yes, the car does have the springs.  You will find them under the distributor rotor.

Thanks Ken

Now for the question I'm sure you knew was coming.  Where do I find "manifold vacume".  Sorry for being such a DA but I have never done anything with vacume and don't know much about it. Thought it might be an easier way than using a timing light.  Just bought the guage yesterday.  Can I get distributor advance springs from Autozone etc?

Thanks again
Neil

 

Any vacuum souce connected directly to the intake manifold.

Examples:  Vacuum line to the transmission.  To the brake booster if you have power brakes.  PCV valve.  If you have a Q-Jet, the top passenger side corner of the carb where the line connects to go to  any air filter connector.  Any line connected directly to the intake, and not the carb.

AutoZone does not have the advance springs.  NAPA might.  Summit, Jegs etc. will.  At one time these were common, but it getting more limited due to drop in demand for the cars that use them, and are still being driven.

Thanks Ken

I'll try the power brake booster vacume line tommorow. 

Rgds Neil

[QUOTE=YellowLT1]

cthulhu

Hooked up the vac guage to the line running between the carb and the distributor.  Turned distributor to peak vacume (went from 10 to 17).   Car idled higher so I turned it back down to 800 rpm with idle screw.  Car did not run well when I accelerated - rough.  What did I do wrong?  I read your comment about replacing distributor springs.  Do I even have those in a transistorized ignition (71 LT1)?

Thanks for any suggestions

Rgds Neil

[/QUOTE]

did you recheck for peak AFTER you turned the idle back down..  you have to have manifold vacuum peaked at IDLE speed..

it sounds like you peaked it..  then dropped idle..  and didnt re-peak

cthulhu

OK I peaked vacume (turned distributor counterclockwise) then reset idle then repeaked.  Still runs rough after about 2000 rpm.  Found a vacume advance spring kit at a local speed shop and will try new springs later today as I am pretty sure mine are original.   If that does'nt work for me I can always set it back like it was (distributor about an inch clockwise from where it is now).  I will let you know how it works.

Neil