Author Topic: 1967 4 speed, should I have a dual diaphragm VAC?  (Read 3288 times)

Offline mikelj5S230

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1967 4 speed, should I have a dual diaphragm VAC?
« on: July 31, 2014, 11:35:38 AM »
I am looking at my newly acquired '67 390 4 speed, and I see just a single diaphragm VAC, routed to the ported vacuum on the carb.  My thermostat housing is not correct, as it should have a threaded fitting for a vacuum control valve, I think.  Did the '67 4 speeds have a dual diaphragm VAC with one side hooked to that valve in the thermostat housing?  Thanks for any info.
I don't always downshift, but when I do it is near a Prius so they can hear me hurting the environment.

Offline J_Speegle

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Re: 1967 4 speed, should I have a dual diaphragm VAC?
« Reply #1 on: July 31, 2014, 10:10:55 PM »
Guessing that your car is not a Thermactor car since you didn't list it


This chart (scanned from a Ford document) should help



............. Did the '67 4 speeds have a dual diaphragm VAC with one side hooked to that valve in the thermostat housing? 

According to the charts and the pictures I have of 67 S codes - no. Single diaphragm attached to the passenger side of the carburtator at the metering block. To the square brass elbow
« Last Edit: July 31, 2014, 10:14:35 PM by J_Speegle »
Jeff Speegle

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Offline TLea

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Re: 1967 4 speed, should I have a dual diaphragm VAC?
« Reply #2 on: August 01, 2014, 07:20:23 AM »
+1. Only on Thermactor
Tim Lea  Shelby concours judge MCA, SAAC, Mid America

Offline mikelj5S230

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Re: 1967 4 speed, should I have a dual diaphragm VAC?
« Reply #3 on: August 01, 2014, 09:46:17 AM »
Thanks guys, no, this is not a thermactor car (Chicago DSO and not listed on build sheet or Marti), I should have mentioned that. 
I don't always downshift, but when I do it is near a Prius so they can hear me hurting the environment.

Offline Bob Gaines

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Re: 1967 4 speed, should I have a dual diaphragm VAC?
« Reply #4 on: August 01, 2014, 01:01:16 PM »
I am looking at my newly acquired '67 390 4 speed, and I see just a single diaphragm VAC, routed to the ported vacuum on the carb.  My thermostat housing is not correct, as it should have a threaded fitting for a vacuum control valve, I think.  Did the '67 4 speeds have a dual diaphragm VAC with one side hooked to that valve in the thermostat housing?  Thanks for any info.
No your thermostat housing should not have threaded fitting .It should be a one year only C7AE marked unit not C5 like what you have .It is also used on the 67 GT500 . it has a physical different appearance not just a number change . Look on the Mansfield site for a pic.  Does anyone have  distributor Tim's contact info handy ?    The single port vac diaphragm on your dist is the incorrect because of the style not because it is a single port unit.
Bob Gaines,Shelby enthusiast, Shelby collector , Shelby concours judge SAAC,MCA,Mid America Shelby

Offline carlite65

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Re: 1967 4 speed, should I have a dual diaphragm VAC?
« Reply #5 on: August 01, 2014, 01:06:45 PM »
http://www.428cobrajetcars.com   but looks like the site is down.
« Last Edit: August 01, 2014, 01:09:03 PM by carlite65 »
5F09C331248

Offline mikelj5S230

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Re: 1967 4 speed, should I have a dual diaphragm VAC?
« Reply #6 on: August 01, 2014, 01:11:40 PM »
No your thermostat housing should not have threaded fitting .It should be a one year only C7AE marked unit not C5 like what you have .It is also used on the 67 GT500 . it has a physical different appearance not just a number change . Look on the Mansfield site for a pic.  Does anyone have  distributor Tim's contact info handy ?    The single port vac diaphragm on your dist is the incorrect because of the style not because it is a single port unit.

Thanks Bob, I have seen a thermostat housing that has the cast bulge on the side of it, but not tapped and threaded for the eventual distributor vacuum control valve, like this one but this says late '67 so has a C8 part number? 
http://www.ebay.com/itm/151324175426?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

I think I am looking for a VAC that has the threaded nipple that fits into it for the vacuum line, right?
« Last Edit: August 01, 2014, 01:13:53 PM by mikeljgt500kr »
I don't always downshift, but when I do it is near a Prius so they can hear me hurting the environment.

Offline J_Speegle

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Re: 1967 4 speed, should I have a dual diaphragm VAC?
« Reply #7 on: August 01, 2014, 01:46:04 PM »
......... The single port vac diaphragm on your dist is the incorrect because of the style not because it is a single port unit.


+1 

Like the left example - not the right. Ignore the arrows - picture was made to illustrate some other details and just handy  ;)




Mike - I guess you have checked the engineering number on your dist already just in case
Jeff Speegle

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Offline mikelj5S230

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Re: 1967 4 speed, should I have a dual diaphragm VAC?
« Reply #8 on: August 01, 2014, 01:53:32 PM »
I haven't checked it yet, but will, where would I find the number?
I don't always downshift, but when I do it is near a Prius so they can hear me hurting the environment.

Offline J_Speegle

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Re: 1967 4 speed, should I have a dual diaphragm VAC?
« Reply #9 on: August 01, 2014, 02:01:41 PM »
I haven't checked it yet, but will, where would I find the number?


Red arrow - engineering number (generic example shown)

Green arrow - date code

Jeff Speegle

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Offline mikelj5S230

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Re: 1967 4 speed, should I have a dual diaphragm VAC?
« Reply #10 on: August 01, 2014, 02:34:31 PM »
OK, got it, but not real clear, here is what I think it says:

C7AF (maybe OF? not real clear) 12127 (clear) AA (clear)

Date code:  very faint stamp, but looks like:  6M26 (could be 28)
« Last Edit: August 01, 2014, 02:40:54 PM by mikeljgt500kr »
I don't always downshift, but when I do it is near a Prius so they can hear me hurting the environment.

Offline Bob Gaines

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Re: 1967 4 speed, should I have a dual diaphragm VAC?
« Reply #11 on: August 01, 2014, 03:40:32 PM »
Thanks Bob, I have seen a thermostat housing that has the cast bulge on the side of it, but not tapped and threaded for the eventual distributor vacuum control valve, like this one but this says late '67 so has a C8 part number? 
http://www.ebay.com/itm/151324175426?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

I think I am looking for a VAC that has the threaded nipple that fits into it for the vacuum line, right?
No that is a 68 truck thermostat. Vac pod like Jeffs single port picture.
Bob Gaines,Shelby enthusiast, Shelby collector , Shelby concours judge SAAC,MCA,Mid America Shelby

Offline Bob Gaines

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Re: 1967 4 speed, should I have a dual diaphragm VAC?
« Reply #12 on: August 01, 2014, 03:43:24 PM »
The BB thermostat housing is very hard to find. If you can't find one PM me because I may have one as it is a often missing detail piece on a 67 GT500 also.
Bob Gaines,Shelby enthusiast, Shelby collector , Shelby concours judge SAAC,MCA,Mid America Shelby

Offline mikelj5S230

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Re: 1967 4 speed, should I have a dual diaphragm VAC?
« Reply #13 on: August 01, 2014, 10:03:45 PM »
OK, got it, but not real clear, here is what I think it says:

C7AF (maybe OF? not real clear) 12127 (clear) AA (clear)

Date code:  very faint stamp, but looks like:  6M26 (could be 28)

In researching that engineering number (though the date looks OK), it appears to be not correct for my car, as it decodes as a 390 2V C6 application.  So guess I need to start a search for the correct distributor as well.
I don't always downshift, but when I do it is near a Prius so they can hear me hurting the environment.

Offline mikelj5S230

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Re: 1967 4 speed, should I have a dual diaphragm VAC?
« Reply #14 on: October 17, 2014, 06:41:54 PM »
The BB thermostat housing is very hard to find. If you can't find one PM me because I may have one as it is a often missing detail piece on a 67 GT500 also.
Finally found one, thanks Bob!
I don't always downshift, but when I do it is near a Prius so they can hear me hurting the environment.