1973 SD Transam 4 spd 1 of 72 built

[auwrestling]

Originally Posted by black69

Another point of information is this car has a close ratio 4spd (few made?) and has the more desireable rear end ratio (3:42). This car would be in the 13 second range which was amazing for 1973. On the other hand, a 73 SD w/automatic with air conditioning would have a different rear end ratio (3:08) that would put it at a disadvantage. That version would be in the low 14s.

Not all 73 SD 455s Trans Ams were created equal. This is one of the fastest ones that put it into the performance range of 70 hemi cars, etc. which was just mind blowing for the times.

The more I learn about this car, the more I like it....

Got addicted to these cars in mid 70s and have owned many super dutys .Still have my 73 Red TA SD 4Spd I found locally 40 yrs ago this month . Best muscle car built!

[flyingn]

holy crap is that nice!!!!

[olredalert]

Originally Posted by njsteve

Sorry about that, my typing overtook my memory recall ability. The close ratio Borg Warner Super T-10 started in 74 and was used in the 74 SD455 cars. The SD455 still had Muncies in 1973 but if I recall correctly, it was the M20 wide ratio. The regular 455 got the close ratio M21, (the M22 got dropped after 1972).

BTW, all the transmissions used the "M" in front of the number regardless of who made them (not just Muncie) and what year.

There's some SD455 trivia on the trans question half way down the page here: http://www.angelfire.com/mi/jamos1/sdtrivia.html

----I'm sure that the wide ratio M-trans helped that 3.42 geared SD get those kind of quarter mile times......Bill S

[auwrestling]

Originally Posted by olredalert

----I'm sure that the wide ratio M-trans helped that 3.42 geared SD get those kind of quarter mile times......Bill S

Yes much better off with wide ratio , I've had both .

[Stefano]

Looks like Tommy Lembeck's car. It was for sale at MCACN VIP.

[L78steve]

Originally Posted by njsteve

3.42 was the rear end ratio for stick cars and 3.08 was for the automatic cars with or without A/C. (No A/C allowed in stick cars). All the four speed transmissions were the same internally and were no longer built by Muncie in 73.

You are quite correct- these cars are scary fast. And to think that they accomplished all this with 8.6 to 1 compression!

If there is one version to have of a SD455, it would be a stick car. (Unless you're old like me and need to be refrigerated and have the shifting done for you) :-)

The 3.08 was for auto with A/C. Auto or stick can be had with the 3.42 w/o A/C. I had a 74 SD Auto no A/C with 3.42, unless 73 was different for the auto and 3.42.

[njsteve]

That is correct. From personal experience I think the autos run better with the 3.08 rather than the 3.42.

[black69]

Originally Posted by njsteve

That is correct. From personal experience I think the autos run better with the 3.08 rather than the 3.42.

Here is some info out an attached link on the performance related to rear end ratios:

Where the SD-455 Trans Am dropped to low-14 second quarter-mile range was when it was equipped with both the automatic transmission and air-conditioning which gave it a mandatory 3.08 rear axle ratio.

Link of reference:

http://www.firebirdnest.com/index.ph.../9-1973transam

[black69]

Hey, I think a relative to this car just sold.
http://www.legendarymotorcar.com/inv...55sd-1178.aspx

[70post]

It is a cool car. If it's the same car that was in the Austin, TX area, now sans the Screaming Eagle decal on the hood, then I know it well.