I am installing my 12 bolt tommorow. I was wondering i am going from 3.23 stock rear to 3.42 gears. Would the speedo just be off?

 

Its almost a 6% error. Your speedo will indicate 63.5 mph at a true 60 mph. Your odometer will rack up 1,059 miles for every 1,000 miles actually driven. You might also find a problem with the shift points, hitting the rev limiter.

 

Thanks Injuneer

I am just going to put it back in storage till i a tunercat or hpp.

I also have to fix the missfire that i have going on. Not sure if its the opti or a burnt wire.