[MrLT9]

Ok i have a 1996 BRM with tow package my rear end say i have 2.93 and i wanted to put 3.73 in it would i have to get my pcm tuned or my speedometer would be off but ill be fine to drive right???

 

[1slow96]

Can it be driven? Yes... Does it need a "tune",also yes.

 

[Z09B4U]

In my case I hit the rev limits during WOT shifts. So in my experience tuning is mandatory.

A proper tune will correct the speedometer and make the best use of the 3.73.

You need a new reluctor for the ABS to maintain resale value and possibly for vehicle inspections in your area.(state or insurance)

 

[1slow96]

If one doesn't change torque converter to a quality 9.5" in the 3000 stall range.
They're leaving a lot on the table ,and this also requires a tune to compensate for.
pcmperformance.com

 

[The Stickman]

I have heard that damage can be done to the trans without a tune.

 

[1slow96]

Don't know about damage? Maybe... In my experience it did not shift "right" due to shift points being off in normal driving. Didn't drive it hard until the PCM was swapped out. Driven beautifully ever since.

 

[Marky Dissod]

I have heard that damage can be done to the trans without a tune.

The transmission line pressures for 2.56 & 2.93 Caprices, Roadmasters, & Fleetwoods (including but not limited to V92) are less than those for 9C1s / WXs (or V4Ps).

Back before the Great Data Misplacement of Aug '09, some people prematurely upgrade to a larger throttle body, but would not tune for it. This would lead to less line pressure for any given throttle position or road speed.
The already barely adequate 2.56 / 2.93 line pressures become insufficient in the context of a 52mm throttle body - or egregiously insufficient paired with a 58mm.
Until the main line pressure tables and some line pressure modifiers get increased, a larger throttle body is a bad idea.