Birdstheword

i would like to get a slightly bigger gear , what are my options ? . BTW car is all stock .

SKELITOR117

iTrader: (3)

Senior Member My A$$.


https://www.thirdgen.org/gears

https://www.thirdgen.org/forums/faq-board/336194-thinking-4th-gen-
rear.html


https://www.thirdgen.org/4thgenrear

Go for Posi rear end, with 3:42 gears.

spurgeon76

Well, do you have a 10 bolt or a 9 bolt rear?

Birdstheword

my rear end is 9 bolt . i just hate how long it takes to get up to speed , probably help my MPG too since i would have to accelerate as much to reach the needed speed .

JamesC

iTrader: (5)

Installing new gears requires some expertise (IMO) and tools that aren't normally found in a do-it-yourselfer's tool box. Best bet is another rear, a third- or fourthgen with the ratio and brake type you desire--along with limited slip perhaps. Considerations where a disc brake rear is concerned: the appropriate combination valve, the appropriate speedo drive and/or driven gears, and the appropriate parking brake cables.

The 10-Bolt FAQ may also provide some helpful information.

JamesC

//<86TA>\\

iTrader: (14)

Putting taller gears will make the car accelerate a bit faster, but it will be running at a higher rpm. Fuel mileage will suffer, not increase.

rarebmx

iTrader: (6)

"Needed Speed" and yes, in quotes for a couple reasons - never heard that before...

I have 2.77's and on the street seems to be fast enough - I am leaning toward 3:42's but with this 700R4 I'm worried that this first gear won't even be used for much. It does not stay in first long at all with 2.77's and 3.42's seem to be the popular route.

spurgeon76

Finding a 10 bolt from the junkyard and swapping it in is the easiest/cheapest route. That's my plan for this summer.

SKELITOR117

iTrader: (3)

It depends on if you drive more on the highway, or more around the city. Changing to taller gears means you won't have to mash the gas peddle as much when you driving around the city to get up to speed, meaning less fuel consumption. However, if your driving on the highway and really only need to accelarate moderatly once, then you at a stable high speed for a long distance, your mpg will drop. So, taller gears equal better city mpg, but worse highway mpg. The 305 TBI gets about 18 mpg city and 28mpg highway. After a swap to taller gears, city mpg should inproove to about 21mpg, and highway should drop to about 23-24. I know I'll be doing mostly city driving, so I'll be swaping out to some 3:42 gears. Nuf said as far as fuel consumption goes.

JamesC

iTrader: (5)

JamesC

92firebird 305

i went from a 2.73 open to a 4th gen 3.42 posi disk rear and i get about 20mpg in the city not sure on highway yet mad a big difference

zenish

grab a rear from a v6 camaro car.most are 3.42.

Birdstheword

I will look into a v6 rear end, any tips for what I should look for, avoid etc.

zenish

if you go to the camaro tech data area you can see which year v6 cars came with 3.42s.the v6 rears are the same as the v8 rears.im running a v6 rear.

D&S 85 IROC

I have a 85 IROC with 305 tpi, 700r and a posi 3:42. The only thing is the crummy gov lock diff. I changed it out for a auburn limited slip. What a difference

85T/A350

All 86-89 V6 cars have 3.42s. Other years vary depending on transmission. I just took one out of an 88 Firebird.