I did a swap to a t-5 a long time ago and didn't have the opportunity to get the speedometer gears until recently. I have already installed the drive and driven gears based on what the parts guy sold me. I told him I was planning on putting in a 3.42 in the near future and I have 245-50R16 tires. He sold me part numbers 14071731 and 14090592.

Currently I have a 2.73 rear end and I know 2nd gear @1500 is 20 mph based on the police trailer thing that tells you how fast you're going. The speedometer says I'm going 18mph.

It seems to me for any given tailshaft rpm, I would be traveling faster with a 3.42 than a 2.73. Unless the tailshaft would have to spin faster to get the car to the same mph.

I confused. Please help.

thanks,

 

You will go slower with numerically higher rear end gear ratios.

4.10s= drag stip @ 100mph @ 5000RPM
2.73s= highway @ 200mph @2500RPM

Not exact but you get the idea.