bought an 88 gta 305 tpi with 700r4 has 410 gears not the right speedo gear yet. adjusted tv cabel still short shifts ? is is speedo gear or governor ? or something elese ? thanks for your help .

 

That's the governor, but really it is the gears. Too much gear for a TPI, too much for a 700R-4s low first gear, and too much gear for the speedometer gears. Even if you can install a 15 toth drive gear, and even if you can get a 45 tooth driven gear, and the correct carrier for it, your speedometer still won't be right. So better to just buy one of those inline correction boxes, like from transmissioncenter.net.
B&M offers a governor recalibration kit.

 

thank you very much . that will help a lot. i did't put the 410 in it. bought it like that, too much gear for a 305 . so i should get a new gov ? and i guess i won't be able to get a cup style speedo gear for ? thanks again

 

If it was my car, I'd go to the salvage yards and hunt for the rear axle assembly from a '90-'92 V6 / auto Camaro / Firebird. Only $100 around here, comes with 28-spline shafts, and a 7.625" 3.42:1 gear set. Not posi, but I'd swap one out of a round-body 4.3L 4x4 S-10 before leaving the yard.
The MPG would pay for the swap in a few months. And it's easier to swap the whole assembly.
As for the governor, you'll find your WOT upshifts will happen later if you do the 3.42:1 axle, even if you don't change the governor.

 

its a drum rear is it already a 6 cly rear ? and all things on it are new was thinking to do a gear change because everything on the rears new brakes . it has the dish size speedo gear can you get a 342,355,373 gear for them ? thanks hoagie