Hi everybody. i have a 73 challenger with 440 and the vacuum advance is not hooked up. is there a reason and will it hurt?

it doesn't hurt. there could be a number of resons that it is disconnected. there are alot of members here that do not use vac adv due to engine mods.some have enough inital timing to make up for not having vac adv.

The extra advance under light load helps the engine burn cleaner. Reduced fuel consumption and reduced sooting in the combustion chamber and oil. Vacuum advance is good for a street driven car. Sometimes its difficult to get it set up with a big cam and big carb but that doesn't sound like your situation.

I'd try to get it hooked up and working. As a start, pull the distributor cap and check for free movement of the advance mechanism. Then hook it up and test drive. On most MOPARs, it works best if the vacuum advance is hooked to a ported vacuum. The ported vacuum is covered by the throttle blades at idle so there is no vacuum. That way the vacuum advance doesn't change the timing at idle. Vacuum comes on as the blades are open. If you don't know which carb port to use, hook up a vacuum guage to each one. When you find one that only has vacuum as you open the throttle, you've got it.

welcome! You can dial in the subsystems in order; initial with "vacuum gauge method" then set the total at 36-38 which will require shortening the slots & it is set with vac adv unhooked/hose capped then toss the heavy spring with the long loop and sub in another (MP light or MR gasket) along with keeping the other light OE spring and play with spring tension keeping it just under pinging at WOT THEN plug in the vac adv & work with it. The short version: post what you have now for inital and total and what rpm the total comes in at and look down in the dist under the plate & see if the heavy spring with the long loop is still in there and is there any pinging?

Hook it up to a ported vacuum source on the carb. You can adjust at what vacuum level the vacuum advance starts to come on by putting a small allen key into the nipple on the distirbutor's vacuum can and turning.

ok before you guys start the op down the path of ported vacuum i am going to suggest to the op that he do a archive search in the tech section of moparts and read the article on ported or manifold vacuum source. it will serve him good to understand the two, also a conversation with don at FBO will be helpfull. as far as adjusting the vacuum can how does he know where to set it if he does not know what kind of manifold vacuum he is pulling i.e.. if he has 16 inches of vacuum it does no good to set the can to come in at a value greater than 16 inches. how does he know where to set it? by the way 3/32 is the allen wrench size and he will need a vacuum source with a gage so that he can see when the plate starts to move at a certain vacuum. use the google search at the top of the moparts page. go to page 3 on the google page and look for " why use ported or manifold vacuum for vacuum advance" hope this helps.

here ya go. read through these articles. it may help ya understand it all a little better...

Thanks everybody for your help.