Vacuum De-advance?

[mcmcgowan2001]

A quick up date since my "too much CAM?" post. I put the 65 110 engine in the 66 body and got some tags. It was running well and taking me on almost daily beer runs. coming home I turned a corner and might have accelerated too hard out of the turn and blam! Generator light. Car is still running. Pull over and open the hood and sure enough the fan belts off. Shut it off and go to put it back on (always carry tools) and notice.......... no rubber on the harmonic balancer. It's in two pieces. 50 year of drying i guess. Get it home, call Clark's , replace balancer and fire it up. Total gutless now so i check the timing. Cant find the mark, so i move the distributor about 3/4 of an inch and there it is past 15 deg. car want's to die. rev it up. Do this a few time and get the mark to 12 deg, idle about 750. Purrrrr. Hit the throttle and it dies. Again and again this happens. Start watching the timing mark while applying the throttle. If the throttle is applied slowly, the timing advances to the right and goes up to 3000 RPM. Sounds good. If you romp on it, the timing mark goes to the left into the negative, backfire, or it dies. when this happens there is a lot of sucking sound at the carbs. What do you think. Distributor? Vacuum leak? ..... I spent two hours and i am hoping you guys (and girls) can help. Thanks

[funvairs]

A quick check for vacuum leaks:
Spray carb cleaner around the carb bases. An increase of RPM indicates a leak.
Connect a clean hose (You are going to put in your mouth) to the vacuum advance unit. Suck on the hose. Watch the advance arm going into the distributor. Does it move out? While sucking on the hose, plug the end with your tongue. Does it hold vacuum? If yes, move to the choke pull offs. Same test. Does the arm move into the pull off and does it hold vacuum? If equipped with a Powerglide, check to see if the modulator holds vacuum using the same test.

[terribleted]

Be careful sucking on the trans modulator. You could get some trans fluid in the hose if the diaphragm is failed.

[flat6_musik]

I think you've got your vacuum advance cannister hooked up to intake manifold vacuum, and when you "romp on it", the manifold vacuum instantly drops and that nice advance you're seeing on your timing light.......goes away in an instant. Try the ported vacuum port, or no vacuum advance at all.

[64powerglide]

Post a photo of the engine bay if you can. Someone might notice something that's not correct.