TMK the dist. vacuum adv. should be hooked to the ported vacuum nipple on the carb. If you look up your model on the holley website or have the instructions it will explain which is ported or timed vac. and which if full vacuum (what I believe you are hooked to now).
From Barry Grant website:
Also, if this is an old or original dist., did you check to see that the vac. adv. is still working? After 40+ yrs. the rubber diaphragm inside dries out and splits = no vac. adv. change.
It's easy to test the vac. adv. - remove the dist. cap so you can see the lever that comes out the back of the adv. and hooks to the dist. plate. Pull the vacuum line from the engine tree and suck on it, you should see the lever pull into the adv. when you draw enough suction. If it doesn't move I'd get a new vac. adv. - write down the ford # on back side of your dist. housing and they can get it at the parts store ~$15. I've had 2 mustangs '70 and '67 and both had dried out vac. adv. Half the people I ask find their's bad and changing it improves driveability and mpg.
Jon
From Barry Grant website:
Ported or timed vacuum for spark advance to occur with throttle opening.
Also, if this is an old or original dist., did you check to see that the vac. adv. is still working? After 40+ yrs. the rubber diaphragm inside dries out and splits = no vac. adv. change.
It's easy to test the vac. adv. - remove the dist. cap so you can see the lever that comes out the back of the adv. and hooks to the dist. plate. Pull the vacuum line from the engine tree and suck on it, you should see the lever pull into the adv. when you draw enough suction. If it doesn't move I'd get a new vac. adv. - write down the ford # on back side of your dist. housing and they can get it at the parts store ~$15. I've had 2 mustangs '70 and '67 and both had dried out vac. adv. Half the people I ask find their's bad and changing it improves driveability and mpg.
Jon
