1st Generation 1964 1/2 - 1973 - Questions & general discussions that apply to a specific year > 1970 Boss
70 Ported Vacuum Switches (PVS) Distributor Vacuum Control
J_Speegle:
Was doing some research helping out a need on another site and came up with a little info I thought I should post/share here for members
The ported vacuum switch PVS was attached to the engine at the thermostat housing on most V8 engines used in 1970 Mustangs and controlled the vacuum to the vacuum advance housing attached to the distributor
The C8AE-A version that had been used through 69 production apparently continued to be used and made up into fall of 1969. Latest C8AE-A version I've got records of is from August 1969
D0AE-A version with the Pat. Pend markings were introduced into production in late 1969 (earliest date I've found on one has been October 1969) A later version with a larger sensor/bulb, lack of the Pat Pend lettering and a reinforced upper nipple can often be found also. Since there are no dates on these I've got no evidence of when they started to be used on a production engines in Mustangs. The latest date I've found on a Pat Pend D0AE-A version has been April 71
NOTE: In the date code stamping a letter was placed between the month and year (as shown in the dating parts article in the library) The letter is believed to indicate the supplier/maker of the part.
Sorry some of the pictures below show the valves/switches in their unrestored condition. The are examples for only markings, design characteristics and other features in this discussion
C8AE-A compared to the D0AE-A Par Pend version
Comparing D0AE-A Pat Pend version verses the later D0AE-A switches/valves. Differences - date or lack of date - upper body marking - large verses smaller bulb/sensor
Reinforcement added to the later D0AE-A non-dated version
specialed:
The 3 nipples are shorter on the doae than the c8ae version & both types of doae was used starting in 70 & I think the 2 doae versions was a vendor change. What I have found on the 2 doae types used depended on the size of the engine & which engine plant assembled the engine & when it was assembled depending on the vendor type used. These vacuum trees usually don't get changed & if you study certain ford size engines from 68 -74 you can doc the changeover. In 75 ford made a d5ae version also.
J_Speegle:
--- Quote from: specialed on July 24, 2016, 01:27:18 PM ---The 3 nipples are shorter on the doae than the c8ae version & both types of doae was used starting in 70 & I think the 2 doae versions was a vendor change. What I have found on the 2 doae types used depended on the size of the engine & which engine plant assembled the engine & when it was assembled depending on the vendor type used. These vacuum trees usually don't get changed & if you study certain ford size engines from 68 -74 you can doc the changeover. In 75 ford made a d5ae version also.
--- End quote ---
Thanks Ed for your input and sharing your experiences.
Have you paid attention (I haven't) to which ones came on the more common (for restoration) 70 cars? Boss 302- Boss 429 and the CJ
Will check my pictures to see if I can find any clue - difficult given the pictures and the small size of the details we're looking for
Its possible that with the change from the 68 in which we've documented two suppliers (one marked the switches with a "K" and one with an "H" - likely Holley) when they changed to the new design the "H" versions kept the date code pattern (since they continue to be marked with the "H" and the supplier identified by the "K" dropped the date as a way to track batches or issues.
Again thanks for the sharing :)
sah62:
--- Quote from: J_Speegle on July 24, 2016, 04:32:08 PM ---Its possible that with the change from the 68 in which we've documented two suppliers (one marked the switches with a "K" and one with an "H" - likely Holley) when they changed to the new design the "H" versions kept the date code pattern (since they continue to be marked with the "H" and the supplier identified by the "K" dropped the date as a way to track batches or issues.
--- End quote ---
For what it's worth I'm still trying to dig up any documentation at all to confirm our suspicion that the "H" and "K" were used to identify suppliers. I had thought that "K" might stand for Kelsey-Hayes, but I haven't found anything at all to suggest that K-H made emissions parts. Does anyone know any other Ford suppliers whose name starts with a "K"?
Bob Gaines:
--- Quote from: sah62 on July 25, 2016, 09:10:43 AM ---For what it's worth I'm still trying to dig up any documentation at all to confirm our suspicion that the "H" and "K" were used to identify suppliers. I had thought that "K" might stand for Kelsey-Hayes, but I haven't found anything at all to suggest that K-H made emissions parts. Does anyone know any other Ford suppliers whose name starts with a "K"?
--- End quote ---
Kem MFG CO is one, Kysor is another.
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