Thank you, I appreciate your help. I did the math and got it wrong last time. I'm glad to say that I got what you got so I must have gotten it right this time.
When I put these numbers in it...

Hi I opened up my rear end and found out that I have 3.42 gears instead of 3.23 as stated before so can anyone help with the speedometer scalar numbers on a
'94 Firebird Formula LT1
4L60E...

Thank you I will try adjusting the Scalar base

And thanks for the OE values, I will start with that.

Hi I have a '94 Firebird Formula LT1 and my Speedometer reads 3-4mph faster than my GPS speedometer App.
I have 3.23 gears, 4L60E automatic transmission, 315/35ZR17 Nitto NT555 G-2 tires on 11"...

Thanks I will check it out

Hi Everyone, I am looking forward to being in this forum. I am working on my '94 Pontiac Firebird Formula LT1. It was setup as a 1/4 mile race car. He had raised the compression and ran it on...