[64woodwheel]

I came across this Manifest from a Pontiac plant built 64 GTO w/ tripower and 3.90 gears.

It is coded as metallic brakes 69(2), standard axle preference saf-t-track axle 70(3) , and 3.90 gears 71(P).

So, why is a 3.90 coded as a standard axle preference saf-t-track and a 3.23 coded as a performance axle preference saf-t-track in the second Manifest posted here?

The preference depends on the application such as with or without AC, Trailer, Auto or SM, and engine type. A 3.90 in a GTO was a special order and did not fall under a category of economy, standard or performance preference as far as coding is concerned. I guess Pontiac had to code it as something though, so they picked standard.

According to the axle chart I posted earlier, a 3.23 is considered a performance axle preference for Police and Taxi versions of the Tempest with either a 6 cyl. or 326 2 bbl. with auto trans, and no trailer, and with or without AC. It doesn't really explain why a GTO with a 3.23 would be coded as performance axle preference. Any ideas?

[johnta1]

Here's what I know:

The Tripower GTO engine came with the 3.23 gear as 'Standard' option after Jan. 1964.
(whether or not it was considered a performance ratio)

So, a 3.90 for it would be 'Performance'

[johnta1]

One other thing I forgot about.

The 76/78-X9 engine is coded for a 3.73-4.33 gear only.
The 76/78-XW engine is coded for 3.08-3.55 gear only.

The '9' tranny is also coded for the close ratio transmission I think?

[64woodwheel]

Originally Posted by johnta1

The '9' tranny is also coded for the close ratio transmission I think?

I think it's true that a GTO with a close ratio 4 speed would have a 9 stamped on the engine for the transmission code, BUT so would a car with a M20 and a 3.90.

[64woodwheel]

Originally Posted by johnta1

One other thing I forgot about.

The 76/78-X9 engine is coded for a 3.73-4.33 gear only.
The 76/78-XW engine is coded for 3.08-3.55 gear only.

Yes, this is outlined in the chart I posted a couple of days ago here:

Originally Posted by 64woodwheel

The numbers are stamped on the front of the passenger side by the timing cover.

[remy30006]

not sure if this is a possibility but somebody had suggested to me that there was a 4 pin heavy duty carrier, Could that be a possibility? I am going to try to call PHS this week to see if they had any thoughts.

[remy30006]

I called PHS and asked them about the 9K code and she did some checking came back and told me that 9k is just safety trac with 3:23 gears and performance axle doesn't mean anything in this particular situation.