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Author Topic: '68 390 Distributor Vacuum Advance Units  (Read 1863 times)

Offline Oz390

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'68 390 Distributor Vacuum Advance Units
« on: September 04, 2010, 08:52:57 PM »
Looking to put an original dizzy (C8OF-D) back on my '68 C6 S code.  Rebuilt and recurved to factory specs.  Trying to determine:

1. was the original a single or dual diaphragm? (I have one of each)

2. what would the pros/cons be for the two units?
« Last Edit: September 04, 2010, 11:31:08 PM by Oz390 »
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8R03S : 76A I 2A 15M 72 5 U
8R01S : 65A B 2A 28M 72 7 5 - Factory GT
8R01C : 65A M 2A 01E 72 2 W - Cal Special
8F01X : 65A I 2A 2G 20E 24 1 U - EXP500 repli-bute

Offline gtamustang

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Re: '68 390 Distributor Vacuum Advance Units
« Reply #1 on: September 07, 2010, 02:56:20 PM »
Being a 72 DSO, I would expect to see a dual diaphram vacuum advance. The two different vacuum advances was to address better emissions through the operating temperatures of the motor (cool to normal operating temp). I really do see it as a pro/con, rather it is what
Ford did to improve the emissions of the motor.

Regards,
Pete Morgan
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Offline Bob Gaines

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Re: '68 390 Distributor Vacuum Advance Units
« Reply #2 on: September 08, 2010, 03:20:16 AM »
In 68 and 69 it is common to see a big block with manual transmission using a duel advance and the automatic with a single advance. Bob
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Bob Gaines,Shelby enthusiast, Shelby collector , Shelby concours judge SAAC,MCA,Mid America Shelby
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