Adjustable Vacuum Advance Diaphram????

Where can I get an adjustable(allen wrench) Vacuum advance diaphram for our mavericks?

 

Crane sells one under the part number 99607-1. Mr Gasket also sells one cheaper but I cant find the part number.

 

I didn't think they made them for Fords, I tried to buy one a few years ago, and couldn't find one. I'll check back to see what you get.

 

http://www.summitracing.com/parts/CRN-99607-1/

 

I can't find the mr gasket one anymore so I guess it's not being made anymore. But yeah like i mentioned Crane has one, and Jeff was kind enough to post you the link!

 

Thanx guys, just bought one from Amazon, $45 shipped, hope it works

 

why not just get a spring kit and adjust the mechanical advance? Its easier than changeing the vacuum advance and more predictable based on rpm than the vacuum.

 

Did that....had a speed shop here in town recurve the dist, but the timing still shoots up to 45 degrees and she still pings more than I would like, so I have been told to try the adjustable pot. With the vacuum off the dist and plugged it sounds great with no detonation, just gonna get bad mileage that way.

 

Exactly why you want vacuum advance, it's sensitive to engine load, not rpm. Cruising down the highway at barely above idle rpm, the throttle blades are almost closed, very lean mixture. You need a lot of ignition advance to fire the lean mixture. Not enough rpm for mechanical advance to give you what you need.

I bought mine at Pep Boys.

 

That makes sense. Couldn't you use a looser spring to accomplish that too and then use the different bushings to limit the amount of total advance? I haven't had to mess with much vacuum related timing as my MSD dist. has mechanical advance only. Plus it wasn't realy meant to be a daily driven street car.

Guess there is alot of variables when you are tuning for more than to just get through a 1/4 mile as fast as you can at wide open throttle.

 

That would just make total advance come at a lower rpm, still wouldn't give you the 45*-50* or so advance you need to light off a lean mixture under light load.

 

Standard ignition part # VC31

 

the mech timing is for performance the vacumm advance is for fuel econome and drivabilaty if it is a stock 302 with lowcomp heads total mech timming should be about 35* at about 3000 rpms if u dont have more timing when cruzzn down the road about 6-12* vacumm u r lossing fuel milage. that is just a thought my 390 in my pu gets 15 mph it is set at 18 intl 16 deg mech and i have a really stiff spring in the vacumm can with a shim in it to limet the total advace to 8 degrees. when i just had the mech and no vacum it got 11 mph up hill down hill u know the story

 

Can you elaborate on this? If it a factory part? I googled trying to find out if any dizzy came with an adjustable one from the factory. All I found was some people saying yes. But no one ever provided the part number or the year/model.... It would really help out a lot of people if we narrow it down.

 

Back in the late 60s, early 70s, you could adjust the factory cans by unscrewing the fitting/from the front and playing with the internal spring and spacer. They had a cylindrical spacer inside a coil sping between the front fitting and the diaphram. The spring determined how quick the advance came on and the spacer determined how much advance. I've read that early 5.0 distributors came with an allen key adjustable can.