i thought 3.07 didnt exist for these cars ?

40:13 on the ring gear of the axle unde the 83 firebird out here



crappy

thanks

round it up, 3.0769 so its 3.08

yes i know that very well actually :P
lemme reiterate this more clearly/specifically:


i always was under the impression this generation of F body cars did not have a 10 bolt ratio that was inbetween 2.73 and 3.23..

but i dunno why..

hmm...

and i have a habit of saying 3.07 because it carries over from the old truck 12 bolt rears in which were commonly 3.07 ratio..

there was also a 3.40(not the common 10 bolt 3.42) ratio in some of them.. in which is far less commmon however anmd that i have only ever come across one of over all these years..

thanks again

Yes a 3.08 rear end is pretty common in thirdgens. All 5-speed TBI cars have a drum brake 10-bolt with 3.08 gears. And there are several 3.08 ratio TPI 5-speeds as well. I have even heard of a few 305 automatic cars with 3.08 gears, too.

My 91 5 speed had 3.08, wife's 84 auto has 3.08, daughters 83TA auto had 3.23......

Crappy as they are read through a Chiltons or Haynes manual sometimes as they have allot of the years listed with axle codes that are on the outside of the housing.

alot of the 82-84 lg4 auto's got them...my bird started life with them...but now has a 3.45 posi disc 9 bolt under it. there are solutions my friend!

Hey guys, looking for some info. I have a 89 L03 305 TBI with 2.73 gears. What ratio will give my 305 a little go at the wheels? Thanks

I have an 89 with the same motor/trans. I've ran 3.23's and 3.42's, and they're both a VAST improvement over the 2.73's. Either of those two ratios will definitely give you a noticeable improvement in takeoff power as well as pulling stronger through the whole rpm range.

I second Pat. When I had a car like his I did the 2.73 to 3.23 swap and it was great. Cruise rpm stayed ok. Final drive ratio moves from 1.91 to 2.26 which gives you less of a salt flats gear and makes the od actually usable to accelerate.

GM also offered 2.93 gears in '82 & '83 F-bodies. My '82 Z28 had 2.93's and a THM 200C.

Remember any time you change the rear end ratio, you should change the speedo gears in the transmision so your speedometer on the dash will read correctly.

Does anyone know if there was a speedo gear set 1991 model with VSS for 3.23's with a T5? I have never seen one listed. As far as I can tell the 5 spd in those years only came with a 3.08 or 3.42.

Thanks