Info on 3.90 gears
Info on 3.90 gears 
Thunder has them for the 7.5 there is the link,,,,
http://www.thunderracing.com/catalog...&vid=3&pcid=67
http://www.thunderracing.com/catalog...&vid=3&pcid=67
Black Plague
Any results for M6 guys with 3.90's on the street?
Any results for M6 guys with 3.90's on the street?
Not worth messing with the 10 Bolt IMO.
I read that they cam be very loud in the 10 bolt.
I went with 4.10s at the time & I blew the posi (torsion)
in a 2 months. Ruined a quiet, reliable rear.
I have an original 3.42 again from a totaled car.
Also Thunder uses Ratech seals & bearings (Not U.S.)
My installer had to buy another pinion seal because it was too small.
He had to do it twice and it was never quiet because of it.
I complained to thunder and they would not accept any responsiblity.
I read here that they came with 2 sizes but they were not aware of this.
I read that they cam be very loud in the 10 bolt.
I went with 4.10s at the time & I blew the posi (torsion)
in a 2 months. Ruined a quiet, reliable rear.
I have an original 3.42 again from a totaled car.
Also Thunder uses Ratech seals & bearings (Not U.S.)
My installer had to buy another pinion seal because it was too small.
He had to do it twice and it was never quiet because of it.
I complained to thunder and they would not accept any responsiblity.
I read here that they came with 2 sizes but they were not aware of this.
Running 3.90's in the 10bolt and loving them!!! I have run 4.10's and 4.30's in my 10bolt too. With my cam only setup the car use to feel as though it would "fall over/run out of breath" above 6000rpm & now it "feels" as though it pulls strong to 6400rpm.
Mine are pretty much dead quiet but I contribute that directly to Telly & Terry at Futral MotorSports for the 1st class install they performed.....
Mine are pretty much dead quiet but I contribute that directly to Telly & Terry at Futral MotorSports for the 1st class install they performed.....
