I have a chance to get a 3.73 posi rearend for my car. But I would like to stay streetable.

Is anyone running 3.73's with a T-5? Are they a pain in the *** on the freeway? What RPM are you running at when your doing 80mph?

 

I used to. That's how my car came stock.

About 3200 at 80. That's with the better OD gear (.73) as opposed to the crappy one that comes in the LG4 and TBI cars (.63).

 

Man that is pretty high. I am used to 2.73s and a 700r4 though. 1750rpm at 70mph. I am actually below my power band most of the time. It sucks.

 

Do it. It will wake that car up. My 84 came stock with 3.73's and a 700R4 and that was fine (2500@75MPH). I'm running a TKO 5-spd now will 4.11's and it's only about 100 rpm higher at 75. I have no problem cruising around between 70-75 at all.

 

I couldn't help myself but when I read this post I had to chuckle.
I must be old or something, I am not from the overdrive generation. I thought that was funny wondering if 3.73 is streetable with an overdrive Man I am used to driving my chevelle with 4.10's and no overdrive. It's not that bad. My daily driver used to be a Nova with a muncie 4 speed and 4.56 gears. LOL. I feel a 3.73 is very streetable even without an overdrive. Where I come from if we didn't have a gear in the car we were a nobody and we were told to put a dress on Don't mean to insult anyone, I just couldn't help myself, Larry.

 

Isn't that the truth!!!

The car I traded in on this 83, was a 79 Z28; 4-speed, 4.10s.

 

check out the equations on the left hand side of the sites homepage. pop in the ratios and itl tell u the rpm or speed or whatever. u have to know your tire radius, i measured mine at about 12.25" - 12.75" about.

 

Well mine is .63. So does that mean I'll be turning more RPMs or less RPMs at 80 MPH?

 

Less rpms. Just do it!!

Punch the #'s in here and it'll do the math.

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

 

Okay! I'm convinced.

I went ahead and bought it.

 

My stock 305 with a '91 T5 and 3.73's feel short legged around town. Even with a light flywheel I can start easily in 2nd. 3.73's are definitely streetable--but if I had a choice, with the stock 305, I'd rather have 3.42's or 3.23's.
I'm about to put on a set of IROC Z 16" wheels, adding about 2" of tire diameter, so my opinion might change. And there's this 4-bolt 350 sitting in the barn that needs to be built, hmmm.
My brother and I once ran a '69 Z28 with a 427, M22 and 4.88's on the street--sold the DZ302 to get rid of it. Good grief, we are old.

 

How small of tire are you running?

 

Right now, they're the stock 14" wheels and tires that came with the car, originally a 305 and 3-speed automatic.

 

I think a larger tire would make a "slight" difference if you're running little 14" donuts now.

 

My rear tires are 275's on 17 inch rims. Will this make any difference?

 

Rbjones is running small 14" tires. I don't know what the diameter is, but I would assume it is much smaller than a stock 215/65/15 or 245/50/16. It could make his car with 3.73's feel like 4.10's if he's adding 2" of diameter to get to the stock 15" or 16" wheel size. If you punch your tire size in this calculator, it will give you the overall diameter. Then it is a direct ratio as to the effective gear ratio with a smaller tire.

I.E. 24" tire versus 26" tire (diameter)

26/24 x 3.73=4.04

You get the idea.

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

 

all our cars got tires with similar outside diameter...approx 25.5" tall +/- 1/2"

 

Without knowing the exact size, it's hard to tell. My old 78 had 14" wheels and those tires where tiny. Maybe rbjones will post his tire size so we can see how tall (or short) it really is.

 

Very well--I went out there and measured the 225R60x16 tires on my parts car and the 205R70x14 tires on my live Camaro.
The 16" tires are 26" outside diameter and the 14" tires are 25" diameter--rats--not as big a difference as I'd hoped.
Adding 1" outside diameter is equivalent to a 4% drop in axle ratio, I believe, changing my 3.73's to about 3.58. A 2" increase in diameter would have been into the 3.40's as commented above--that would have been nice. Maybe the 245's will be a litle bit taller as well as wider than the 225's.
As to overall satisfaction with the 3.73's, I drove over to the next little town out here yesterday afternoon (Snyder, Texas) where they were having a car show around the square--big turnout, a lot of trailer queens. This '91 T5 has gears like a close ratio 4-speed with a big overdrive for 5th, so around town in Snyder I had the advantage over several Mustangs--even got to honk at one sitting dork-like at a green light. The light flywheel, low rear end gears and 3" Flowmaster exhaust wake up the little 305 a bit.
Driving home--65 miles--I took a side trip by Lake Thomas with the T-tops out, cool, green day--total distance: 165 miles, 6.8 gals. = 24.3 mpg., cruising 2400rpm at 70 mph.
So, 305 with 3.73's? Just fine, if you throw the occasional Mustang into the mix.

 

That's good to hear. Hopfully I'll be getting my new rearend installed sometime this coming week.

 

i run 3:73's with a th350 trans (3 speed no overdrive) and its ALOT of fun..i can cruise 70-75 no problem. if i redline 3rd im doing about 120 maybe a little less

 

I agree, 3.73 is not a bad gear without overdrive. I run 4.10's in my chevelle with 400 turbo and I drive it everywhere, no big deal. Although I have a 28 inch tall tire on it though instead of the short 26 inch tire that is common on these 3rd gens. Even so I can go 55 mph at 2,800 rpm and 65 mph at about 3,200 to 3,300 rpm. Not that big of a deal, just can't be in a hurry to get somewhere. I drove accross the country with 3.73's and a 400 turbo, 2,600 miles, not bad at all really. I could comfortably go 65-70 mph with a 28 inch tall tire.
I used to drive my Nova from Cincinnati to Pigeon Forge with 4.56's and a muncie 4 speed. I hang with a group of guys who love gears, without them I would be considered a no-body
We are old school people and have always had atleast one car with alot of gear. My buddies 427 Chevelle runs a 4.10 gear with a 400 turbo and he drove from Cincinnati to Pigeon Forge also no problem, only he did it in 4 hours I asked him what he was spinning the motor and he replied, I just put it on 4,000 rpm and cruised. Gears can take a sad running car and make it feel like it will turn the earth, Gears are where it's at Of course this is an old fart talking Larry.

 

Yeah, when I got my car from my brother in Tallahassee it had the 3.73's and the original automatic. I drove it out here to West Texas over T-giving weekend a year ago--not bad, especially taking US highways about 65 mph, 3000rpm.
Now, though, with the tall 5th it's about right.
Too bad the 700R4 has such a bad reputation--it has a nice set of ratios. And that Gear Vendors o/d is around $2000--geez.
Talk about low, I also have a '52 ****** pickup with the Kaiser flathead six and Timken 5.38's front and rear. It tops out about 35 mph. Someday I'll find an original o/d tranny for it.

 

umm, I'm curious how a higher gear is a "crappy" overdrive.




to the original poster, get the 3.73's. I've got 3.43's right now with my T-5 but I wish I would have gotten at least 3.73's. I'm putting 4.10's in this summer, but I'm also doing a T-56 swap. .5 6th gear won't be too bad at all

 

hey rbjones, Speaking of 5.38's, a buddy of mine I hang with has a COPO 69 camaro, I am sure some people on here would be familiar with this car, L-72 427, 4-speed, and factory equipped with 4.10 gears, all original car except one thing. When he bought this car in 1973 someone had already swapped 5.13 gears in it. Mike (my buddy) drove this car with 5.13's all the time until just recently, about a year ago he swapped in 4.56 gears, he calls them his highway gears now and I am sure it would feel that way after driving around with 5.13's for the last 30 years. I liked the car better with the 5.13's but he could not cross the finish line (1/4 mile) before the engine would lay over, but he kept it matted anyway, man those were the days. Ever since the change to 4.56's I have been trying to talk him into taking the car back to the track, I beleive the car will go faster now that it has less gear, he should be able to keep the engine in the power band through the finish line. He is now hesitant at drag strip passes since the car is so valuable now, but he still hammers it on the street frequently Sorry I got off subject. Larry.

 

Hey, firebirdjones--in the spring of '67 Nickey Chevrolet was selling its dealer-installed 427 Camaros through a dealership in downtown LA, Felix, I think, so my big brother and I went down there and took a test ride. They wouldn't let us drive--wise move. I got planted up against the back window when the salesman hit 2nd gear. I don't remember what gear was in that thing, only that it was black with white stripes and had the "K" in Nickey backwards.
Well, my brother was about to graduate from USC (University of Spoiled Chldren) so they offered him credit, no down payment, but my brother could get a masters if he stayed in school one more year and he decided to do that instead, bought a new '69 Z28 (Corvette Tuxedo Black--no stripes--special order) when they came out, dropped in a big block, and ended up tearing that poor car to shreds with modifications--but that's what makes them rare.
He and I have passed this 3rd gen back and forth, making it better, but it's such a solid example and it's getting so good now--5 speed, 3.73 posi, rebuilt front end, cooling system, roll bar, and the interior's out, down at the upholstery shop--that I don't know if he's getting it back.
There's just nothing like a Camaro; and I think the 3rd gen is the best.

 

umm, because a 0.63 overdrive has no *****. My L03 wont turn above 2500 rpm in 5th with a 3.42 rear.

 

Oh man if I had 3.73s I would be turning 3350rpm at 70mph. That is crazy. 3.42s would be 3100. And 3.23's 2900. I think I can live with 2900. For now I will be running 2.73s....according to this I will be revving about 2450...which will hopefully keep my 2400 stall from slipping.

 

I'm running 4.11's with a T-5 and 383SuperRam. It is GREAT on the street, really woke things up from the factory original 3.42 10 bolt. 70MPH is only about 2400-2500RPM, and that's with the factory size 245x55-16 tires.....

 

Looks OK to me....

I can't tell you how many cars I've had over the years with 350s and 400s, and 4-speeds (same deal), and 3.73 gears. Chevelle SS396s, Z28s, you name it. For a while I had a 78 Z28 with its stock 350 and 3.73s, and a 79 Z28 with a 4-speed and 4.10s. I have a 74 Caprice convertible right now, 454/400, and 3.42s in it; and also a 69 Chevelle SS396 convertible that's temporarily out of service, it last had a 427, 400, and 4.09 gears (12-bolt of course).

What you're talking about is completely normal and ordinary, not "crazy" in the least. It's the stock setup for almost all of the old 60s muscle cars. What's "crazy", is thinking there's something wrong with it.

 

I agree entirely RB83L69, I think we are talking to mainly the overdrive generation on here. They are not used to turning any kind of rpm on the highway and everyone seems to be worried about gas mileage too I for one love gears and running that kind of rpm at 70 mph is nothing at all. Also if I was worried about gas mileage I would buy a Chevette I wouldn't be driving cars with V-8's in them.
I have a 56 Nomad that runs a 327 4-speed with 4.56 gears, it's really not that bad. My SS 454 chevelle has 4.10 gears in it with a 400 turbo, I drive it everywhere. Put gears in it, It will make a man of you Larry.

 

For mileage--which is most of the time--I drive a '94 Honda Civic; for cruising, my '82 Camaro; for speed, a '60 Austin Healey with a 327 in it; for light hauling, an El Camino; for heavier hauling, a '70 3-door Suburban. After that, I have to start getting things down off blocks and putting batteries in them or firing up antique tractors--a disease. A few years ago I wouldn't get near anything with a computer--today, if I got sick and had to choose just one car to keep, it'd be the Honda. Hate me.

 

Hey RBJones, sounds like we are alot alike except that last part about the Honda. I still do my best to stay away from computer controlled cars although I bought this Iroc I am already regretting it with all this computer stuff
My daily driver is a 79 Monza with a 406/350 turbo combo, I run a 3.23 gear in it. It has run some easy 12.60's at 110 mph and lots of tire spin. It is from California so a nice rust free car. I drive it everywhere, no computers, easy to maintain. I like things simple. My wife drives an old Jeep CJ, also from california and very solid, no computer stuff, very simple to work on and she loves it so I am happy. Other cars we have, I have a 79 1 ton single axle chevy truck with a 454 and over 30 factory options, including 3.73 gears, I drove it accross the country to get it back here. Very neat old truck I use to tow and haul stuff, it is also from out west, original paint and very solid. And I have some simple mods done to it, it runs 14.70's at 96 mph pretty funny for something that big and shaped like a brick. Other toys include a 56 nomad with 327 4-speed and 4.56 gears, I drove that car in highschool and still have it. That big tank runs mid 13's at 104 mph. I have a 72 SS454 Chevelle that appears stock but runs 11.40's at 118 mph, I bought that car when I was still in highschool also and brought it back from North Carolina. I also have a 70 Firebird Formula with factory ram air, also picked it up from california many years ago, completely stock and running 13.60's at 102 mph. My wifes daily driver up until last year was a 71 454 corvette, all original survivor car with 30,000 miles. I sold it with 46,000 miles on it after a years time, so you can see she had some fun with it. I have had many others too much to list here and waist everyones time, but you get the idea, I am an old school kinda guy and really prefer the old stuff but I am trying to adjust to this Iroc and all its creature comforts and doo dads, with everyones help here I should be able to keep it running Larry.

 

I hate to hijack this thread (well actually i dont care, just being cordial), but what do you plan to do as far as getting the speedo to work correctly?
I am having a PITA time trying to find a driven gear for a T-5 VSS that would be good for my 3.73 rear end...I need to get a 21 tooth gear but I cant find one.

 

You can get a Dakota Digital box for the speedo correction for like $75 at dakotadigital.com - that's what I did and it works fine.

 

firebirdjones--computers are definitely wierd, a thing with no moving parts having so much affect, and you can't get in there and work on it, yet you can adjust it with another computer--sometimes--even to compensate for low gears.
If this '82 hadn't come with a computer I would have changed the cam, the intake, the carb and the exhaust to take advantage of the 3.73's; but it's the factory computer that's giving me such good drivability and mileage with a stock engine and low gears. A non-computer cam would mess it up (Crane tells me) and a higher intake wouldn't fit under the stock hood, so my old-school thinking has to be put on hold for a bit while I just drive the car and enjoy it. If you're getting used to the features of your IROC, it might be growing on you, too.
When I was a mechanic 35 years ago, people would ask me what was the best kind of car to buy and I would always say, "the one that doesn't break," which at that time was a 2-barrel 283 Powerglide Chevy, pre-smog. Today it seems to be a well maintained, EFI, computerized vehicle that's been left completely stock.
As for modifications, I don't want to spend the money on aftermarket EFI, TBI, or any other injection, so my true hot rod, my Austin Healey, will always be pure old school, except I put in a Unilite distributer when the factory dual point gave out a few years ago--you could tell the improvement in spark immediately. It's the part of me that will always be 19, like riding in an aluminum beer can with a high compression, solid lifter, radical cam, double-hump head with almost open headers big journal 327--no interior or insulation. After an afternoon of that, a Camaro with mufflers, a roof and roll-up windows feels like a luxury car. That's largely why I love my Camaro and I guess the computer adds to that dependable, seamless, sporty performance driving. Like your fleet, I guess, it's a work in progress.

 

I hear ya, the Camaro can spoil me in a hurry with all its power accesssories. It's when they start breaking I will start hating the car But I agree, I plan on leaving this car mostly stock, the price of fancy fuel injection does not interest me, just some simple outside bolts ons is probably as far as I'll take it.
My primary toys are the older cars anyway, I have much more fun with them, and they are easy to maintain. Plus I am always sticking money in them even though they look finished, they never are, there is always something I want to change or try to make better, so that is where most of my money goes anyway.
It sure would be cool to hook up with you and some other guys with similar interest in this old stuff. This board is so spread out over the country thanks to computerized technoligy that it would be very hard to do. Too bad, I think I could meet some really cool guys on here. Take it easy, Larry.

 

Well, you never know--thirdgen.org might hold a national meet some day when a bunch of us old guys have time and resources--you never know. We need to check out these gears on a road trip anyway. Or maybe a big regional meet--I've always wanted to take a spring or fall trip out east. But, as you say, I keep putting money into them, so how could I ever afford going to a meet? I think, when the interior is done on this Camaro, with a good set of speakers and the a/c working well, I'll just drive it like it is--no more money--just polish, drive and maintain it, so maybe in a year I could take that east coast drive.
About cars breaking--when I was about 27/28 it struck me that what makes a hot rod fun is being able to close the garage door when it doesn't work, instead of having to stay there and get it running so you can get to work the next day. I really like being able to fire up the Camaro and go for a cruise with just regular maintenance, park it and know that nothing's broken (usually). For the Healey, the weather has to be perfect, the fuel mixed with octane boost and lead substitute, crank it over first to get oil pressure, let it warm up to let the solid lifters and forged pistons size up a bit, then grit your teeth and hold on. It does cruise, sort of, but everybody looks at you and it's so loud you have to shout at the guy next to you--pure pleasure.
When I had my big block '78 pickup--like your '79--it bugged me for three years that all that power was plugged up with smog equipment. I finally de-smogged it, put in a Crane cam, did the heads myself, Performer manifold and 750 Holley--all quality internal parts but built to tow. The PAW kit cost $450, machining $500--and it went from 230 advertised hp to 375 hp and 450 lbs. torque, still on regular gas--and got 10% better mileage. So, we can't sit down and talk it over--the internet is OK.

 

Yeah right! That's what I always tell myself too.

 

johnjm22--I forgot to mention the new 16" tires; and I'm missing one IROC center cap, should touch up the paint in a few places--couple of louvers in the sides of the front fenders at the same time--maybe put in a set of 3.23's for the road...yeah, you're right.

 

firebirdjones--would it be allowable on this site for you to post a foto of that Nomad? If not, OK--just one of my favorite cars ever, moreso than the '55 or '57. Another reason I like the 3rd gen: it's an excellent base, comes apart and goes back together like that Nomad but you don't destroy the value.

 

Wow RbJones, I am flattered you would want to see a picture of that. I am not very computer literate so I will have to figure out how to post a picture here or better yet have my wife figure it out. I don't know if it is allowed or not, Could someone here answer that question? I don't want to affend or violate any rules. I know most have their 3rd gens and that is all they like, I personally like anything GM and have owned about everything at one time or another. I have a small collection of different stuff now including this 88 Iroc. Although I preffer the old stuff and grew up around it, This Iroc is still pretty cool, I like the body style, I just have to learn the electronic part of it and familiarize myself with this car, which is why I joined this site. Everyone has been very cool to me here so far and I have learned alot about it already. As far as meets, I wouldn't mind making a trip out west myself, maybe there will be a get together that way, I have always been fascinated with Texas, as a matter of fact we want to move out that way sometime in the future, we have been looking into Arizona also, tired of this Ohio weather and the desert climate would do my allergies good.
Maybe I could send you some pics via your E-mail, would that be better? That way I would not ruffle any feathers here. Let me know, I am taking my wife and son to the zoo today, I will be back this afternoon, take it easy, Larry.

 

firebirdjones--check out our regional site, lots of good stuff going on in Texas. I'll send you a pm.

 

Hello All,

I was wondering how I can find out if my 1983 trans am daytona pace car has a 3.73 rear gear? It is the 305 crossfire injection motor with the 4 speed automatic.

Thanks,

Ray

 

Take off the cover and look.... same as any other car.

If I was the betting kind, I'd be willing to bet that it doesn't; or at least, that it didn't come that way.

2.93 was more typical for those.

 

After I installed my 4.10's I was talking to my Dad about someday upgrading to a T56 and how mush they cost. He said I should just stick a muncie in it. I laughed and told him I wouldn't be able to drive on the highway anymore. He just walked away shaking his head, now I understand why.

 

Exactly Larry.