I know I am driving you guys crazy and I am trully sorry but I did not get a clear answer yesterday on setting my timing. Totally restored 1970 440-6 rebuilt by a pro with 175 miles on it. When I set the timing to 10 degrees BTDC the car tends to run labored and backfires once in a while. Yesterday I put a vacuum gauge on the intake and it read 14 and was at the bottom of the late ign. timing area so I moved the dist. until I got up to 18 and in the green normal area and the car ran perfect so I got out the timing light and low and behold I had moved the mark on the balancer 20 degees. It was now 10 degrees oppisite. What is wrong here? I id this with the vacuum advance hooked up, is that wrong? Is there anything wrong with setting an engine with a vacuum gauge and forget the timing light. If it starts easy, does not ping thigs should be fine or am I missing something.

I generally set the timing w/o the vacuum advance hooked up. At least for total advance. You need a good light w/ an advace on it or timing t ape to do it right. I plan on setting my slightly modified 440-6 at 36* total at 2400.
Here's what I do (it's good to have help) start the car turn the distrib until it sounds good...take a vacuum gauge to the carb and turn your mixtures until you get the best vacuum. Then have a buddy hold it at 24-2600rpm, unplug the vacuum advace (make sure you plug the vac line) and check your timing. Turn the distrib until you get the final advance you want (I'd sat between 34-38*) lock it down. Then adjust your idle speed down to about 800 or so, re-check and adjust for the highest vacuum and check initial. Take it for a romp it it feels flat try a little advance.
All in all if you start it and it runs fine (after warm up) and the performace is good lock it down. You can always try some fine tuning at the track for a little ET gains.

I had similar problems last year tuning my fresh 440-6 pack, to make a long story short it ended being the outer ring on my harmonic balancer had spun almost 90*
You may want to start over by doing the initial timing just to verify that your balancer is still zeroed.

just put it where it runs best and forget it.. who cares what its supposed to be? dan

I have my 440+6 locked at 22 initial w/no vacuum advance and 14 degrees of mechanical advance. I just put a cap on the vacuum advance module and put the hose over it to appear that it's hooked up. :-)

Since the eng is running well I'd pull & plug the dist vac line & see what you have now for initial for reference. As a general rule you want your total(without vac adv) on a BB to be ~36-38 degrees & enough initial to where it idles good(a wilder cam needs more initial) & the right slot length for both ends(initial & total) to be right and the right springs for no detonation(from initial to total) when you get on it and if it does not ping(from too much timing) then no damage is being done only that there may be power being left on the table if it can be further advanced(w no pinging)(within those timing guidelines).

thats what I am thnking, was hoping to find someone to agree with me.

swingin/72, lighten up you are going to get him confused

I'm funnin too, I just forgot to put in my usual smiley face