89rs358

lookin to regear my 89 camaro with a 350, holley 750, pretty sure it is running the stock gears right now and they are way to short , im in 5th gear at like 35mph, not sure what gears to go with tho, i am not looking to race the car, just get it to where i can cruise along on the highway at 70mph and be under 3000rpms, right now i can only do about 60 and im at 3100 and she doesnt sound like she likes it very much , any help would be awsome, also i live in chattanooga, TN so if you know any shops that can do it somewhat cheap that would be even better!, thanks!

EDIT-
also the car has a cam upgrade, and stock 350 heads

89rs358

ive been doing some more research on this (which i should have done first) and it seems my understanding of how the gear ratios work was backwards, so perhaps the previous owner put a higher ratio rear end in, is there anyway to tell what gears it is running currently? im thinking i need a lower ratio for highway use, altho i dont want to go to low because of the cam correct? i used a few ratio calculators from google, and from the numbers it gives i either have 3.73 or 4.10 (more towards the 4.10)

jmd

iTrader: (4)

Cam detail would help, but where your powerband is located would be better.

I.E. a 1985 L69 / T5 / 3.73 Camaro can be shifted in the low 5000 range or with a cam possibly in the low 6000 range. In either case, the 3.73 gears work great in that car with that powerband. But, it would be entirely drivable with 3.42 gears.

Also, what T5 is in your car? Many / most V8 T5s have .62 overdrive. Others don't. There is a service tag on a tailhousing bolt of a stock T-5. Starting with 1352 is a number that should tell you what the trans. is and thus what gear ratios. Some had a decal on top of the trans. with that number which is harder to access.

And, is your speedometer accurate? Assuming the odometer and speedo are both good as a unit (this is more of an issue w/ mechanical speedos but I digress,) go cover 10 miles. Does your trip odometer cover between 9.9 and 10.1 mi. on that trip?

If your tires are around stock height (26") then overdrive * the final drive * 1000 is about what your rpm should be at 70mph. .62 * 3.73 * 1000 = over 2300. So maybe you don't have that fifth gear, maybe you have 3.90 or higher gears.

You have a lot of maybes in there. Changing the differential fluid and gasket so you can count the ring and pinion teeth would be a good first step.

89rs358

thanks for the reply, and sorry for the lack of information, i did not build the car and have only owned it for about 4 months and it has been snowing for 2 of those so ive only put 200ish miles on it .
will check the number on the transmission in the morning, the spedo is waaay off, not sure if it is because of regearing tho because it is not a set amount off, as in if im actually doing 50 it might say im doing 80, if im doing 55 it might say im doing 95 or something, but it is off, none of the stock gauges work, not sure on the odometer will check it out, the tires are stock 25.6 inches, it might just be im shifting way to early as well, the only manuals i have ever driven were newer imports and my jeep, i usually shift around 1500-2000 rpms, which is why i dont like being at 70 mph and 3700 rpms, it still has plenty of power at that point, i can just touch the gas pedal and it will pass anything, just want to get it to where i can take it on road trips without holding it that high for 5-6 hours, unlesss it is supposed to be that high because of the cam
also not sure exactly how much horsepower it is pushing i know the previous owner built it to race, the a/c has been removed, blower moter, everything

EDIT- ok this is the rear end it has- 393 12 Bolt rear -, would 393= 3.93 ratio or does that mean something else? *facepalm* im such a n00b
here are the ratios for the t5 it has - 2.95,1.94,1.34,1.00,.073

EDIT X2- i guess i could post what i plan on using the car for if that would help in deciding what gears i should go with, i would like to drive it down route 66 one day, there is a car show in ocean city MD i used to go to every year in the summer and i would like to drive this car up there one year and enter it, 10-13 hour drive, my first trip would be down the floridas coastal highway, also a 10-15 hour drive, so mostly highway use, i would like to be able to cruise along at 70 and have it at 2500rpms, also right now im avging about 8mpg highway would like to be at around 12-15 highway if possible

jmd

iTrader: (4)

Well, jack it up on 4 stands and put it in neutral.

Stick a screwdriver through the pinion yoke and rotate it just under 4 times. If it turns the tires once, there's your 3.93.

While it's up, pull the speedo gear sleeve / vss from the T5. If the gear inside the trans. on the output shaft is purple, it's probably a 7 tooth which you want. If it's red, it's a 9 and you have a good reason to pull the trans. to change it to the 7. Count the teeth on the driven gear too.

If you don't feel like pulling the trans., stick it in 5th, pull the serpentine belt, have a helper chalk and watch the driveshaft, and use a ratchet to turn the engine over 1x. If you get about 1.35 turns of the driveshaft, there's your .73.

At this point if those are what you have and its a good shifting world class T5, you may want to do one of two things. Find used or buy $300 (I'm guessing) in new parts to change 5th gear to .63 or .59. Or go with a T56.

I'd hate to tear down a properly set up 3.93 rear when 5th can be changed pretty easily and without setting any backlash.

jmd

iTrader: (4)

I last ran up to the Rt66 parts of AZ Sept 09 with a friend from here and we met up with a friend from IL who drove all the way to CA.

You'd be okay with a .63 / 3.73 combo (or equivalent rpm) in my opinion which is basically what you're saying with the 2500rpm thing. I wouldn't want any more RPM than that on a trip. I've had 3.73s with a 1995 T56, and 700-R4 and 200-4R and a couple T5s.

89rs358

i did not know you can change out the 5th gear by itself, that helps a lot, i will do those tests in a few days when i can get it to a friends with a garage and post what i come up with (been in trouble for working on my cars in my apartment complex to many times lol) one day i want to swap it for a t56 but dont have the money right now, i will look into changing out the 5th to .63, thank you!!