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Discussion Starter · #1 ·
I finally modified the secondary piston again & this is the latest deal.
Drilled the secondary piston with a 8mm-.320" carbide drill to a depth of .535". The piston now weighs 9.8 grams.

Next I found a lighter spring.

Just installed the above in my 67 mustang & now full throttle upshifts come in at 5800 rpm's.
The trans has a transgo shift kit, but I left the stock pressure valve spring in so the shifts would be firm but not slam.
I had to purchase 25 of these springs to meet the suppliers minimum order.
With more line pressure the shifts may be higher, every application is different.
I am glad to finally hit the right combination, cause its a pain to keep removing the tailhousing to expose the governor.
I will sell this spring for $15.00 each which includes shipping if anyone is interested??
What I did was at least get the shifts close to 6000 rpm's.
Note, no mods were made to the large primary piston.

Hope this helps guys, also thanks for all of your previous input. V/R Bill Ambler











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67 mustang coupe 6-cylinder
2003 ford lightning

<font size=-1>[ This Message was edited by: wsa111 on 12/20/06 8:33am ]</font>

<font size=-1>[ This Message was edited by: wsa111 on 12/20/06 8:35am ]</font>
 

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i'm assuming these springs are for a automatic valve body. Cause i thought with a manual you shift it manually unless its a manual/automatic valve body? am i right?
 

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Discussion Starter · #4 ·
This spring is a custom designed lighter spring just for this application. Bill
 

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changing the governor secondary valve to part# C4OP-7C053-A will make your stock governor shift at 5800.

Paul
 

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Discussion Starter · #7 ·
Mattstang, I had to back off the modulator & part throttle upshifts are a little higher than before, but fully driveable.

Paul is this part# C4OP-7C053-A still available??? Bill
 

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Will this also help increase the auto/downshift speed...
above about 25mph, my shelby will not downshift automatically to 1st...

Also...is it still available, and where...

Thanks

<font size=-1>[ This Message was edited by: markboss on 12/25/06 3:47am ]</font>
 

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The piston was available the last time I bought some - that was a few years ago.
There are also four governor assemblies available:
26615A, B, C, and D
the only one that was around in 64 is the A series, C4AZ-7C063-B
I don't have a parts breakdown for the valve bodies but if someone else did or has used one and knows what speed it shifted at we might be able to label one of the governor assemblies as "better" than the others.
Paul
 

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On 2006-12-22 11:14, Mattstang65 wrote:
does this mod effect part throttle shifts?
Mattstang65,
generally speaking changes in the governor will not affect the part throttle shifts of a stock engine. As you build the engine the vacuum signal goes farther down. At some point the vacuum is low enough that the governor will shift before the modulator does and it will then affect the part throttle shift points.

Paul
 
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