Hi guys,is this rear end the same as the 5spd gears wise?Will it make a good rear end for drag racing? TIA

 

the nice thing about an rear end from an auto is that it was most likely not abused.

I seem to recall that the 84 and 85's all used the same diameter axles. so the strength should be the same, Although diferent brake options were available. the gearing was the same between the 12a manual and auto trannies. 3.9 something. I believe the 13b gearing was 4.x but I could be wrong.

http://mazdatrix.com/g.htm for more info

 

The GSL has 2 clutch disks eaither side, and the GSL-SE had 2 on one 1 on the other. The GSL has a 3.90 gear ratio, and the SE has 4.09, or 4.10 gear basicly. the GSL has a 110X4 bolt pattern, and the SE has 114.3X4 bolt pattern. IMO If your doing drag racing put a extra clutch on either side of the GSL. Your driveshaft should bolt up, unless its Pre 1984. I'm not 100% on 1983,

If your's is a 79 it won't work. You will need another driveshaft.

 

Very good information.....Thanks!

 

Thanks for your input,the car is a1981 I bought for parts but my son wants a project car and this 7 has a straight body and minimal rust so its a good candidate. Its the 3.90 better for drag racing?These gear #s confuse me all the time

 

If you have low horse power the 4.09 or higher would be better letting you accelerate faster, if you have high hp the 3.90 or smaller would be better. the way gear ratio works say you have a 3.90:1 gear ratio, your driveshaft would have to spin 3.9 times to turn the diff 1 revalution. but if you have lower numbers its harder to turn than the 4.09 so it takes from acceleration.

since the car is an 81 you will need the driveshaft from an 84-5 manual trans, I don't know if the auto driveshaft will work or not. It might.

I hope this cleared up gearing for you some

 

sorry I posted mis info The GSL-SE has a 4.076 ratio