I have a 396 mild build up in a AT car right now it has 2:73 gears i want to change them out this winter but not real sure where to go this is a nice summer 1 day a week car I was thinking around 3:73 or 4:10 even 4:11 where should i be?


thanks

The question is what do you want to do with the car?
If you just want a good all around cruiser I would say go with 3.55's.
If you want more get up and go, and don't mind spinning a little higher on the freeway go with the 3.73's.
If you just want to melt tires all day and mainly cruse around in town. (55 or less) Then I say get the 4.11's and burn rubber! :thumbsup:

I dearly love my 3.31's!!

BUT nobody is re-popping them!!

pdq67

If you ever plan on doing anything like the Power Tour, or want to go on a long trip to a car show, then you will hate the 3.73 or 4.10 gears. A 3.55 is a little too much for long cruises, but not bad for shorter trips. If you just want to play around town then the 3.73 or 4.10 might be fun.

didnt the 302 Z/28's come factory with 4:10's?

I had 2.73's and 26" tall tires. RPM's @ 65 were 2300ish, and the best 1/4 was 13.5 @ 102 with traction.

Now 3.73's and all else the same was 3300 @ 65 and 13.2 @ 103 with little to no traction. (3300 gets old quick with a loud exhaust)

I would go 3.55's for street duty.

didnt the 302 Z/28's come factory with 4:10's?

3.73's were the norm. I have 3.55's in the '69 and 3.08's in the '67. There's been a many a time I've been out on the interstate in the '69 keeping up with traffic in overdrive and pull it down in drive and think man there's no way I'd like this for very long. On the other hand the 3.55's are great around town and in my case some not so serious strip action. The 3.08's in the '67 do leave some performance on the table around town but cruise pretty good. Based on your nice summer weekend drive I'd say no more than 3.55's.

I have 4:10's and if you drive on the highway alot you'll be better off with 3.73's. I like the 4"10's for drag racing, but a 26 inch tire is about 3700rpm at 70.

this car never goes on the highway (well maybe 1 time a month if i am lucky) so with that said will i feel a difference going from 2:73's to 3:73? or am i better with 4:10's?

The difference between 2.73's and 3.73's will be like getting kicked in the head. You will feel it big time. Perhaps not a good analogy.:)

Just swapped a bbc 68 Camaro to 3:08 from 3:73, there is lots of differance. Engine is basically stock and 4 speed. Between 3:73 and 4:10, I chose 3:73,, but of course I am 5 speed Od. I do lots of hiway now. Anybody going to Biloxi?

Oh yeah, dumb question but are you sure you have 2.73's to start with. Just want to make sure.

yes i am sure they are 2:73's checked by marking tire and driveshaft and also the GM code on the rear

Depending on the amount of hop up you've done to the motor, if you decide on 3:73's (and assuming you know the carrier has to be changed or you can run a spacer set up), you may also want to look into a street converter with a little more stall than stock...good luck.

ok its a 396 30 over i am running the hole shot 2500 converter what else you need to know?

With that set up you should be real happy with the 3.73's. Like I said before good all around gear other than long hauls. This will give you a nice peppy set up.

ok great now to get me a set. Any one recommend who i should use?

What rear end do you have? Is it a 10 bolt or 12 bolt? Do you want to add a posi?

its a ten bolt posi

I have Superior Axle and Gear. There great, strong, set in right away, quite. I have know a few people over the years that didn't like Richmond's for one reason or another.

Will 3.42's fit his rearend guys??

pdq67

If this is the 8.2 10 bolt then you will have to replace the posi to go with the other gears. The 2.73 uses a 2 series and you will need a 3 series. If it is an 8.5 10 bolt then you can use the posi that you have. A good installation kit is a must if you want this to go smoothly. It will have all of the shims and other parts that you will need to set up the gears correctly.

How can i tell if its an 8.2 or 8.5?

If it is the original rear end then it will be the 8.2. Someone could have installed a Nova 8.5. The 8.2 has a 1 1/8 pinion nut and 3/8 ring gear bolts with 9/16 heads. The 8.5 has a 1 1/4 pinion nut and 7/16 ring gear bolts with 3/4 heads and left hand threads. The 8.5 has square lugs that hang off of the bottom of the center casting on each side.

Its the org rear...well now i have to find a new posi unit and gears to make this work? Where is a good place to find what i need?

There are several members "in the business", although there are all very cognizant of the policy's of the board regarding solicitation. Big Gear Head, Jody's Transmissions, and Muncieman come to mind, send some PM's or emails. The members here take car of eachother very well.

If you have the 8.2 then you might want to consider swapping it for the 8.5 Nova 10 bolt. The 8.5 is stronger and there are many more options for it. The parts area a little cheaper too. You can also upgrade it to 30 spline axles.

maybe someone can help me figure the right gears i need I was looking at 2 choices 1st. 373 2nd.410 that the final drive number i wanna be at the tire size is 26" so what will i need to get these numbers?

Are you going to drive this on the street or just race it? If you plan on driving it a lot then you might not be happy with either one of those. You RPMs on the highway will be pretty high and you won't want to drive it very far. If this is a race car then you might want to go with the 4.10.

this is a summertime car only goes out on the weekends i dont put many miles on it at all so i am not really worried about highway driving

I'd go with the 3.73. I had a 3.73 in my '69 SS396 Camaro and it was all I wanted to do to drive it 36 miles to Owensboro. I had a 4.10 in my '72 SS454 Chevelle and it was just too much. I now have a 4.11 in my Camaro, but it has 32 inch tires on it, so it drives like it has a 3.50 in it.

Again with what you keep saying I would recomend the 3.73's. There real fun around town and not to bad on shorter trips now and then.

ok so i am going to go with the 373's but keep in mind i have 26" tires on the rear so how would that change my final ratio?

namz111
Good choice. :thumbsup: I ran that same set up for about a year befor I got my 200-4R. I looked back to see what you are running for a trans, and I didn't see it. The final gear ratio is 1-1 in 3rd gear for 350 and 400 transmissions any way. I'm assuming you have the original 400 in there still. So you would be running about 3100 rpm at 65 mph. Like I said not bad for short trips, but it gets old on long hauls. This may help. http://www.xse.com/leres/bin/gearratio?title=SS+%23670+with+MM6+manual+and+GU6+ 3.42+gears&rpm=6000&mph=65&gear1=2.52&gear2=1.52&gear3=1.00&reverse=2.90&axle=3.73&tire=diameter&diameter=26.00&circumference=81.68
If you are running a 350 your gears are.
1st-2.52
2nd-1.52
3rd-1.0