BrainFreezE

iTrader: (2)

I am thinking of putting Moser 4:10 on my 6 speed trans am. what kind of RPM are you getting at 70-80 mph? trying not to waste too much gas.

BALLSS

my T56 is .50 6th with a 27" tire. 1900-2000 rpm @ 80 mph

google gear ratio/rpm calculators and input your 411 for specifics

user_guest3214

I had 4.56 gears, .54 6th, 26.5" tall tires, and pulled about 2200 RPM at 70 mph.

The problem wasn't 6th gear or highway. It was the fact 1st and 2nd gear were totally useless. You could start out in 3rd gear without any problem. I now have 3.73 gears with the same trans and it runs like a bat out of hell now.

BrainFreezE

iTrader: (2)

so basically 1 and 2nd is just tire burning lol good to know.. im guessing the rpm would be way different on a 4 speed automatic right?

slt200mph

iTrader: (42)

Not much of a fan of the 12 bolt. Get a 9 inch or a S60 and really be bullet proof. Especially if you like a 5000 rpm banzai launch. The 3.73 was the best setup for me with a car that spends 99% of its time on the street.

BrainFreezE

iTrader: (2)

Whats the difference from a 12 bolt and a 9 bolt? when I bought the car it came with a 12 bolt. so I am just thinking of changing the gears.

slt200mph

iTrader: (42)

9 bolt??? I think you mean 9 inch. When it comes to strength of rear ends a 9 inch Ford or a Dana 60 are much stronger than a 12 bolt Chevy. It all depends on what you are going to do with the car. I have broken a few 12 bolts in my day so I'm not a big fan of them. On the other hand a Dana 60 and a 9 inch Ford are what you would call bullet proof.

BrainFreezE

iTrader: (2)

well not looking to do anything crazy! mainly for street use the occasional street race when someone might temp me which won't be alot maybe take it to the strip a few times a year.

high impact

iTrader: (5)

I run a 12 bolt with a 6spd and if its set up correctly they are plenty strong with out the additional weight. I have 3.73 gears but will be going to 4.10 soon. IMO the 3.73 aren't quite enough but I have a monster cam and run 27 inch tall tires at the track. On the street with toyo drag radials I can't hook hardly at all already.

blue99fbody

iTrader: (5)

the 12 bolt is still not strong enough with the 6spd if your drag racing alot i broke mine a few times before going to the 9" on the street its fine but track is a crap shoot just dont put it on drag radials at the track run a bias ply

user_guest3214

I do not know the weight of your car, but the heavier the car, the more gear you want. Mine weighs about 2300 pounds, so the 3.73 works great.

HioSSilver

iTrader: (8)

3.90 is a good gear if your running a stock height tire. Take a look at those before you buy.

SNLPerformance

iTrader: (15)

I recommend this link to get an idea...
http://www.f-body.org/gears/

user_guest3214

That is a cool site! Thanks for the link!