Carb,Distributor, & Vac Questions

[james singleton]

Here is what I have currently on my 66'- 200cid engine: a Motorcraft 1940 single barrel carb w/SCV, a Load-A-Matic distributor, and a Petronix elect. ignition! Here is what I would like to do: I would like to install a back-up carb that I have which is also a Motorcraft 1940 single barrel but is a "NON" SCV type carb. I am thinking about buying a 69', or later, stock distributor and installing the Petronix elect. ign. in this new distributor! Do you see any problems with this set-up??? Also; when do you need the dual vac cannister instead of the single vac cannister like I have now??? I know that many people seem to go the DuraSpark dizzy, or other dizzy route, but since I recently installed the Petronix set-up and the fact that I have this "non" SCV carb, I thought I could have two different set-ups! One set would be the orginal Load-A-Matic dizzy with the SCV carb, and the back-up set-up would be a "non" SCV carb with a latter dizzy that is a 69' or newer! This way I would be able to use the Petronix elect ign. system in either set-up??? Make any sense??? Thanks, Jim

 

[Bort62]

Why? Just go with the duraspark and you won't need backups.

 

[bigcatchdaniel555]

Sounds pretty complicated with everything like the 2nd carb. I gonna agree with Ian and apply the KISS principle (keep it simple stupid). I would bite the bullet and get the draspark Ive had both and the duraspark far out performs the pertronix. Its more reliable too.
Dan-

 

[66 Fastback]

The Pertronix for the Load-a-matic and the Pertronix for the later style distributor are different part numbers. But I think you may be able to do some grinding and get the Load-a-matic Pertronix to fit the later distributor. I do not remember if the Pertronix ring interchanges between the tow distributors.

If you had to purchase both a later distributor and a pertornix, then the cheaper alternative would be the Duraspark.
Doug

 

[james singleton]

Thank you all for your comments. I didn't want my previous post to get too long (or complicated), so I omitted one detail, and that is that I suspect that either the SCV is bad on the present 1940 carb or else one of the passages is plugged up!??? I am not getting vacuum @ the carb, even over 2,000 rpm's. Since the Petronix is newly installed on my Load-A-Matic dizzy, I thought that buying a 68' or latter dizzy (which is only $28) might be a way to keep the Petronix and go with my back-up 1940 carb which is a "NON" SCV carb! Also, when is it that you need a dual vac cannister instead of the single?? Thanks for the input! Jim

PS. 66 Fastback, Actually I had to file/grind a little bit off my existing Petronix in order to get the air-gap set correctly; and I have read where others had to do the same thing.

 

[66 Fastback]

James,
I went the same route as you, thinking I could adapt the pertronix from the Load-a-matic cheaper than going the Duraspark route. When trying to grind it to make it fit the later distributor, I slipped with the grinder and cut a wire right at the pertronix module.
I run the 68 distributor triggering an MSD box right now.
Doug

 

[james singleton]

Doug, which 68' distributor are you referring to; a stock Ford dizzy??? If you are using a stock 68' dizzy, are you also using the Petronix with that dizzy, or is that why you mention the MSD?? Sorry for my confusion! Jim

 

[66 Fastback]

To be honest, I will have to check the car and see if I purchased a Pertornix for the '68 distributor.
I have an old Vette that I just use the points to trigger the MSD and those points have been in there over 10 years.

If I recall, I initially set up the Mustang Load-a-Matic to trigger an MSD box with points. But for some reason it still consumed points and I think I purchased a Pertronix. Then I converted to the Weber & '68 distributor and I don't recall if I bought a new pertronix after trashing the old one. I'll check this evening.
Doug

 

[66 Fastback]

I do have a Pertronix on the 1968 distributor.
For your 1966 vehicle, I would stick with the single vacuum cannister. The dual vacuum cannisters are for later vehicles that had some early emissions controls. They also had different timing advance curves.
Doug