What gears should I use?

[1997v6ixxr]

Hey new to the site. I have 1997 heavily modified 5 speed Firebird. My mechanic is rocommending 4.10 gears but this car is still a daily driver. It's NA with Abbott Racing Heads, Abbott Racing upper and lower ported intake, Intense Racing Stage 3 NA cam, Diamond 10.5:1 pistons, Pacesetter Headers,Cat removed,3" Flowmaster exhaust, 24# injectors, functional ram air, 17x10 wheels, 4 piston Wilwood calipers, 13.5" cross drilled rotors, aluminum 1 piece driveshaft, stock rear and gears plus full suspension upgrades. What do you recommend for street/occasional strip? LSD is already planned. :burn:

[techsan23]

Re: What gears should I use?

I vote 4.10"s unless your doing alot of hwy driving

[1997v6ixxr]

Re: What gears should I use?

I do combination hwy/city everyday. What rpm range am I looking at w/4.10's at 60mph? Are 3.73's an option?

[techsan23]

Re: What gears should I use?

- 4.10 rear in 4th gear = 3160RPM
- 4.10 rear in 5th gear = 2370RPM
@60 mph

found this in an old thread. Put 4.10 or 3.73 into the search option and you will find several similar threads. I am very pleased with my 3.73's, but many people that go to 3.73's wish they would have gone with 4.10's.

[1997v6ixxr]

Re: What gears should I use?

I know my cam doesn't start to really pull 'til the upper 3k range. I don't want to be one of "those" that regrets it.
Thanks.

[FirebirdGT]

Re: What gears should I use?

I have 3.73, work fine city and highway.

[1997v6ixxr]

Re: What gears should I use?

I thought 3.73's would be perfect given the combiantion driving and little racing(legal racing) I do. I had 3.73's in my '78 TA with a worked 403 and they were great street and strip. That sled would pull high 12's with those gears and slicks! That motor made power at a lot lower RPM than my 3.8 does.

[ssms5411]

Re: What gears should I use?

I have GM motive 3.73's with my A4 and the VS cam and after every shift I'm above 3000 RRMS where my cam is at its sweet spot, so If your cam is the same way, then I would do 3.73's, they will probably be quieter also than the 4.10's. While your in there a T/A cover with the stud kit would also been a great investment while making the rear a little stronger at the same time and reducing rear end temps. Add some RP rear end oil and your good to go.

[1997v6ixxr]

Re: What gears should I use?

Good info! The Intense Racing Stage 3 NA Cam makes power around 3500-3700 through 7000!! The valve lifts w/1.60:1 rockers is 542"/529", and LS 110. Despite what my buddy recommends I think I'll go with 3.73's. I've already planned on the TA cover and stud kit when I get the LSD and gears. I'm pretty sure my car was originally equiped with 3.23's but I need to check the RPO to be 100%.

[LETZRIDE]

Re: What gears should I use?

you can also go with a 3.90 gear...step down from a 4.10, and a step higher then 3.73's....I got em, Im pretty happy with them...

[1997v6ixxr]

Re: What gears should I use?

I have thought about going with 3.90's. What is your rpm range at highway speed, say over 70mph?

[LETZRIDE]

Re: What gears should I use?

I have an automatic so I am not sure this applies to you or not...but at 70mph my tach reads at about 2600....hptuners says around 2400

75mph I read off 3000rpm....hp tuners says its around 2600-2700rpm...It eats gas at this speed...or used to before the cam anyways...I think that had something to do with the PE tables, so hopefully I can fix that issue...

here is a useful website for you if you want to compare gear ratios and see where you will approx. be shifting and reving at...

http://www.f-body.org/gears/