[unruhjonny]

Originally Posted by 392Wrangler

Also this car has the M21 close ratio as is shown on the PHS. But a bulletin on Feb 9th 1970 (Again referring to Rocky’s book says you had to order the 3.73 gears set with that trans, but my PHS does not show Performance axle ratio. It does show safety trak though.
Any thoughts?

I believe that the way it worked is best understood by looking at the options through the lens of a period sales book (of which I have a copy; bought it probably twenty years ago):

#358 4-Speed Close Ratio manual (Safe-T-Track req.)
- 22687 with 37R Axle: $195.36

Later on:

#361 Differential Safe-T-Track (Required with 37R Axle)
- 22387-22487-22687: $42.13

The 'performance axle' option would only show up as a cost option for a Formula w/o option #358, but because your car has option #358, the performance axle was already included.

This is why the close ratio muncie was always (for 1970 & prior) associated with a lower gear set;
Only with the options shuffle for the 1971 model year did the close ratio not always require a lower gear set.

Does that shed some light on to the situation?

You made me do some searching - nice car!!

LINK

[Baron Von Zeppelin]

. The 'performance axle' option would only show up as a cost option for a Formula w/o option #358, but because your car has option #358, the performance axle was already included.

That is pretty much the synopsis I'm trying to evaluate towards the 70 TA's with 3.73
Some with just HD Radiator
Some with HD Rad & Perf Axle

Using this Formula in comparison does seem like it's very possibly an indicator towards the TA's also.
You worded that very well.

Just need enough 3.73 Van Nuy cars with accompanying Bsheets and Invoices to nail that to the TA's.
But it has credibility in context.

[keith k]

Originally Posted by unruhjonny

The 'performance axle' option would only show up as a cost option for a Formula w/o option #358, but because your car has option #358, the performance axle was already included.

This was a mixed bag in '70. Very early production M21 cars like the subject of this thread seem to have not included the cost for the Performance Axle on the invoice, while later cars did. The extra charge appears on all the M21 Formula invoice copies I have for cars with Norwood VINs beginning 107xxx (late March). See example invoice.

[unruhjonny]

Originally Posted by keith k

This was a mixed bag in '70. ...

interesting.

My sales book has an issue date of February 26 1970 - so it's presumably the first issue for the 1970 model year to contain the "1970+" Firebirds;
I had assumed from how this book reads, that the '37R' axle was included in with the option cost - not an additional required option like it reads for #361.

So it's safe to assume that '37R' = #368 ??

Maybe PMD issued an update of sorts requiring #368 be an added cost option if #358 was ordered?

[johnta1]

Here's what I found:

Code - 348
UPC Code - L74
Available Formula; Standard TA

400 ci Ram Air V8 4BBL (RAM AIR III)
Ram Air III: Not available with 2 Speed Auto Trans (352), Turbo Hydramatic Trans (359), or Mountain Performace Axles (754)


Code - 347
UPC Code - LS1
N/Available Formula; Available TA

400 ci Ram Air V8 4BBL (RAM AIR IV)
Ram Air IV. Not available with Air conditioning (582)

-----------------------------------

Code - 361
UPC Code - G80
Standard - TA

Safe T Track differential
Requires performance axle (368) axle


-----------------------------------

Code - 368
UPC Code - G90 Performance Axle

-----------------------------------

Code - 358
UPC Code - M21
Available Formula; Available TA

Close Ratio 4 Speed Manual Transmission with Hurst Floor Shift
Requires Safe T Track Differential (361).

Formula 400 with Peformance Axle (368) - $195.36
Trans Am with Performance Axle (368) - No Charge


-----------------------------------

[johnta1]

Found this (for GTO but probably similar):
(not sure I have a clearer pic)





(at bottom left)


Axle -Sales Code 37R is 3.07 ; UPC is GX1

[Ramairnacho]

Originally Posted by johnta1

Here's what I found:

Code - 348
UPC Code - L74
Available Formula; Standard TA

400 ci Ram Air V8 4BBL (RAM AIR III)
Ram Air III: Not available with 2 Speed Auto Trans (352), Turbo Hydramatic Trans (359), or Mountain Performace Axles (754)


Code - 347
UPC Code - LS1
N/Available Formula; Available TA


400 ci Ram Air V8 4BBL (RAM AIR IV)
Ram Air IV. Not available with Air conditioning (582)

-----------------------------------

Code - 361
UPC Code - G80
Standard - TA

Safe T Track differential
Requires performance axle (368) axle


-----------------------------------

Code - 368
UPC Code - G90 Performance Axle

-----------------------------------

Code - 358
UPC Code - M21
Available Formula; Available TA

Close Ratio 4 Speed Manual Transmission with Hurst Floor Shift
Requires Safe T Track Differential (361).

Formula 400 with Peformance Axle (368) - $195.36
Trans Am with Performance Axle (368) - No Charge


-----------------------------------

Im.still learning this stuff and quick.questiin. The 348 code is tam.air option correct? Is mountain gear a 331 open cou code axel? My formula is ram air but no posi different than this nice 4 speed car and mine has the m40 auto with a/c.