I'm starting to give up....

85_SS_302_Coupe said:

As for the total timing, i'm running a Mallory Comp 9000, which is mechanical advanced. If i go out and set my total timing to about 34, how do i know base timing won't be all crazy?

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The base timing really doesn't effect much. You want as much initial advance as you can run without having starting trouble. I run my timing locked out at 36 degrees with a MSD starter saver that only retards timing only if the rpms fall below 500 for cranking the engine over. Zero low speed drivability problems. If you have starting problems, you can try to recurve the dizzy. Being even two degrees off on total timing will make a huge difference in the power it makes. It's also really important to have max timing early. You should have max advance no later than about 2400 rpms. If the Mallory distributors are like the MSDs, they come from the factory with a really slow curve (heavy springs) which gives max advance too late so you lose alot of midrange power. Need to change them out for the lightest.

For that car with a stock cam, I would set the base timing at 6-8 or so, no more than 10. Check to see if you have a dist advance vacuum regulator, the 79-80 2v cars had one, that gave vac advance at idle. I discontinued mine last month after 27 years... and it runs better. Has a much more stable idle.

The idle vacuum should be a bit higher, but that may improve with tuning.

Fix all the vacuum leaks, or temp disconnect everything and plug it. My 79 still has every single vacuum device and hose on it, although some are not currently in use... Make a good diagram of how it hooks up.

Check the carb lit or data to see what jetting it has. The stumbling sounds like not enough shot from the accel pump, and too lean an idle.

Also make sure you are not losing ignition via bad plug wires, or weak primary ignition wiring, ie, is the coil ok, and wiring to it ok?

I have two carbed Foxes, with Holley 80457's, one with Duraspark/Jacobs and one with all MSD except the dist. I have 62 and 66 main jets, and plenty of idle mixture adjustment, etc. Make sure the accel pump moves as soon as the throttle lever starts to move. This is important with a Holley.

I have an Edelbrock carb on my Chevelle. It runs fine, but I am only keeping it because it came there. I have not tried to tune it yet, other than setting the idle. I only had 12 in vacuum, and 7 cylinders working, and were were able to get it running decently for the last 6 months. I would much prefer Holley.

to check for vacuum leaks first thing you do is put a gauge on it the the car should have 15 to 20 lbs of vac at an idle.... if the needle is jumping around you may have an internal problem... if its low and steady it a possible vacuum leak or ignition timing problem.