Topic: 1970 351C 2v 4 spd distributor diaphragm single or dual?

[BHStang]

Trying to figure out if I should have a single or a dual diaphragm distributor.  Details on the car..1970 Mach 1, 351c 2v, 4 speed close ratio, AC, Ram-air, Power Steering, and power disk.  Built June 10 1970 Dearborn.

I have seen plenty of details on the 4v Cleveland's but virtually nothing else other than suggestions that both a single and a dual diaphragm might be possible on the 2v.  I can say for sure it does not have the dist-o-vac modulator system that the 4v 351s and 2v 302s had.

[J_Speegle]

First welcome to the site. Hope the support and information find here is helpful in your restoration focused needs

Looking through some of my pictures of 70 four speed Cleveland H codes found a couple of examples. Lots of AC cars that block the view plus not allot wwith manual transmissions




Also found this vacuum routing diagram that matches the two port advance

[BHStang]

Thank you.  I have found diagrams for both hook ups of a dual and a single diaphragm.  I have found a few pictures showing a single but also dual.  I am leaning towards a dual setup.  On some things you might say either or would be correct but I really feel like this was not something Ford went back and forth on simply because of part availability month to month.  On the other hand I have found the 70 H code Cleveland's to truly be an oddity.

[J_Speegle]

For 70 and other years  the type of transmission comes into play. Have plenty of singles but they are automatics equipped H codes ignored  those as well as those with replacement single diaphragm installed

We're you looking only at unrestored cars also?  Since that can provide allot of false findings when using a google picture search or similar tool.

Unfortunately Ford didn't label the two diagrams like they did earlier years. Best source would likely be the Electrical and Vacuum Manual but I don't own a 70 version

[cobrajet_carl]

I have a 351C-2V 3 speed 70 mach and it has a dual diaphragm advance. Dizzy is a D0AF-H. No A/C or anything else.

[70cj428]

I'm basically a big block guy but .....

I checked a bunch of manuals here, 1970 edition of the wiring and vacuum diagrams is no help (no engine vacuum diagrams)

70 shop manual :
the good news is that the only 351 that had a single diaphragm distributor was a Fairlane application (351 2V auto in a Fairlane or Montego). All the Mustang applications were dual diaphragm distributors.

I tried to look up the correct distributor for your car but the application list in the 1970 shop manual doesn't differentiate between Cleveland and Windsor
The MPC and the shop manual implies that the correct distributor is a D0AF-H but I've had no luck so far determining if it's a Windsor or Cleveland 2V.
but it's gotta be a Cleveland distributor if it's in Carl's car as they don't interchange....

Any chance you have the stamped ID number off the side of the distributor??

Hope this helps, John

[cobrajet_carl]

Oops that dizzy might have been off of a 351W - I'll have to double check now...

EDIT: The D0AF dizzy is on my 351W. I am not sure my 351C dizzy is original or correct but it is a D0OF-E .

[BHStang]

I'm fairly sure now that a dual diaphragm unit is correct.  The Shop manual and vacuum diagram manual are virtually worthless on the 2v Cleveland's. Information on them is truly hard to come by.  I do have the MPC and that does help...some.  I too found D0AF-H to be what is called for.  Just got one off EBAY in really nice shape, does not look like the casting has ever been media blasted.  It came with the dual.  Adding to the conclusion is that by the MPC it seems to only call for 1 advance unit.  Doesn't say if its a single or a dual but it is only 1 option.  With at least a few known examples coming up as dual that makes me land on the dual as the correct fit.  The fact that there are some 2v vac hook up diagrams out there for a single is still a question, but I'm thinking maybe they were for the handful of very early 70s that got a Windsor.  Now the big problem is finding someone still in the business or restoring the distributor and vac unit.