I have a stock 82 t/a rear end. It has a 2.93 posi.
I will be upgrading the rear end and I was wondering how I should go about this.
Should I strengthen the factory welds and get a some 3.55 gears...or should I get new axles and at the same time get 3.55 gears. What should i do?


by the way. I do not want 3.73 because this is going to be a daily driver. Do 3.42/3.55 and 3.73 differ that much????

 

28 spline would be stronger. But, then you couldn't use your current posi.

3.42's (2-series), welded tubes, stiffener cover would probably last for a good long time as long as you don't really abuse it, and especially if you avoid wheel hop.

Every step in ratio makes a difference. I noticed a difference between 3.08, 2.73, and 2.93 (in that order). Since I have OD, I wouldn't mind 3.73's during the summer.

 

depending on your set up and if you have OD 3:73 wouldn't be a bad choice. there is so much you could change it may be more cost effective looking for a slp posi or 4th gen rear to swap in.

 

ede,

I was thinking about the 4th gen rear end swap.
However is the suspension similar in the back. By similar i mean would I be able to use my torque arm, panhard bar, and all of the same parts I currently have on my 82 t/a w/disc?

 

4th gen rear is direct bolt in, only differance is the width by 3-4 inches. might or will have to run differant wheels.

 

are 3.73's good for a daily drivin 5 speed? and whats the numerically highest ratio for a 2 series carrier?

 

yes its 2 inches bigger on each side (4 total) so youll need different wheels. if you have the BW 9 bolt i would just do the gear swap. those 9 bolts are strong as hell. ive seen people running big blocks using 9 bolts and they hold fine. im positive they are stronger then the 4th gen rears. im currently swapping out my 2.73 open drum rear for a BW 9 bolt 3.27 posi disc. think its worth it? got it for free....

 

hey Kontrax, think i could get a free rear end too?

 

haha sure. just pull one out of someones car when they park at the mall or something. i actually had an 85 trans am i was going to race out. ended up selling everything off the car untill it was a complete frame. found the rear under a pile of crap in the gurage a few months back and say "hey why not swap" anything is better then an open 2.73 drum rear. actually, you can have that one for free when i swap if you like

 

I can vouch for that. I have 3.08's and a buddy of mine has 2.73's. They seem really similar numerically, but his car seams sooo sloooooooooow compared to mine, and we have the same engine. I have another buddy with 3.73's and his car feels like a frickin rocket. It's amazing what a difference gearing makes. I think people overlook them all to often...

 

Yes, and 3.73.

 

yeah!!!
thanks soo much you guys,,,that helps me out a bunch..
so the 4th gen rear is a direct swap but I have to run bigger wheels..
how much bigger.
Right now I have 15 x 8 rims on p255/65r15 rubber.
And no..the current rear end is a 10 bolt.

 

you have to run 4th gen wheels with the 4th gen rear. if you do do the rear swap, you wont need the spacers like you do with the 3rd gen rear, and the fronts just go right on no problem

 

what?

i've been told a few times that 3.xx needs a 3 series carrier? who sells 2 series carrier 3.xx gears?

 

http://store.summitracing.com/partde...ew=32&applid=%

 

i think I will go with 3.42 or slightly higher like 3.55 however I was wondering what final ratio I would get with my th-350c tranny.

 

Well the 1:1 gear, which is 3rd in the th350s, will be what your gear ratio in the back is for the final ratio. As for the rest, take wha the ratio for first is in the 350 x rear gear ratio (i.e. 3.42) and that is the final for first, and same for second gear.

 

wow, cool thanks. i have a 10 bolt rear from a 88 GTA. is that a 7.5 or a 7.625 inch?

 

Same gears fit both.

 

thank you. one more thing

can i just order these gears and install them? or do i need a kit?

thanks in advance

 

anyone?

 

You "could", but the kit replaces common wear items, and provides needed parts to get the setup right.

Some people set up their own gears. The tools & equipment required to do it properly cost enough that it's typically cheaper to have a shop that knows what they're doing set it up for you, unless you plan on doing this on a regular basis (like ede...).

 

I need more opinions on this please.


I do not know if I should go with 3.42 or 3.55 or 3.73.
The drivetrain shop told me I should go straight to 3.73's however I have a th350 tranny which is 3 speed with no overdrive.
I am worried that the 3.73 gears will cause me to rev about 5000rpm in third with not that 3/4 throttle.
I do not want such high rpms because when I began my engine buildup I was focus on lower rpm torque for street driving.
However 100km/h will be very frequent around my area so I just want some more input.

If 3.42 or 3.55 or 3.73 will give me great tire smoking acceleration but will not make me run out of gear prematurely.

thanks in advance

 

well the th350 has these ratios:

1st: 2.52
2nd: 1.52
3rd: 1.00

use our calculations page (here) and use the 'RPM' section to figure out what rpm's you would be at 65mph(for example) or whatever speed you cruise at. try it with the different rear end rations until you find what you are looking for.

 

I'de go with 3.42's since you've got an automatic tranny. You'll have plenty of get-up-and-go, yet still be good on the highway as well.

In addition to this, you'll have room to mod your car this way... you don't want to get a low gear ratio, mod your car, and then find out that you redline 3rd before the end of the 1/4.

 

well if he has stock wheels and tires, he'll hit 112mph at 5500rpm in 3rdgear...not too bad.

 

hey transam88

you you mean i will be at 5500rpm at 112mph with the 3.42's or 3.73's.

If that is the 3.73's...then 5500rpm shouldn't cause engine damage right?

 

3.73's. 5500 is redline for my L98 (350). i think 305's have a 5000 redline?

 

yep, 305's (TPI anyways) redline at 5,000/yellowline 4,500... but he also has a 350 so i'de say he's good...

3.73's or 3.42's would both be great choices, im sure you won't find anything major to complain about with either one.

 

right. that's what i figured out too with my car. im going to get 3.73's just for the hell of it...they should be quick and fun