3.73 or 3.55 for 90 SC automatic?

truedog

Registered User
I think I am going to take the plunge and change gears on my 1990 SuperCoupe. I have heard that the 3.73 is best for the automatic transmission. Will it be too low for highway driving and day to day use? I will not be drag racing the car and top speed is not a big consideration. I may run an occasional street autocross. I mainly am after quicker acceleration off the line and having engine run at a slightly higher RPM around town. The AOD hits second and third pretty quickly and lower gear would help with driveability. My question is, how low? Also, since I am not overly concerned with top speed, can I get by without a chip?
 
I would say go with 3.73's. That way you can just buy the complete Cobra pumpking with the 3.73's already installed with a new traction lock and aluminum pumpking. If you already have the gears, I couldn't find a local shop to set them up for less than $200 and that was with me bringing them the pumpkin. Either way you will have to to the removal/installation of the pumpking yourself.

As for driveability, I love my 3.73's. I go through the traps at about 5200 rpms, but that will be lower without the non-lockup convertor that I have. At 70 mph I'm at about 2400-2600 rpms, versus the 2000 rpms with the stock 3.27's.

You will not need a chip, but you will need a new speedo gear.
 
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