I have the stock 2.73s and i wanna swap out for 3.73s, am i gonna get a significant difference in launch?

 

You'll probably feel a difference, but that 305 (if that is what you have) still isn't a big tire burner.

 

Most members wouldn't recommend 3.73's with a 700R4.

JamesC

 

tranny cant handle it? what gear is reccomended

 

3.73's are apparently out of the power band. 3.42's seem to be what's recommended. A search will provide more info.

JamesC

 

3.73s behind a trans with a 3.xx 1st gear and a motor that won't rev, will LAUNCH you to about 5 mph; and then you'll feel sort of stuck.

Ever drive one of those cars that could just SMOKE the tires sitting still, but can't pass a semi on the freeway at 55 mph unless it's a long downhill grade? That's kind of what that combo will act like.

Just too much gear for the rest of the car. It will force the motor to always be in a range of RPM where it has absolutel no power whatsoever.

Now, do something about the restrictive exhaust, the cam that you could hide the lumps on with Clearasil, and the heads that .... ,,,, ..... ummmm yeah .... , and it could be ALOT more fun.

 

Well I have a 305 and I was just looking for a easy way to run a lil quicker

 

Get 3,23 gears, 3.73 with an automatic V8 combo is a hell no. you will rev to 3500 rpms a 60mph, you can expect 8-10 mpg. 3.73s are made for a t56 imo.

 

my mpg gonna suck with 3.23s?

 

With gas prices the way they are any gear ratio gonna suck.

 

lol good logic, but am i gonna have a drastic drop?

 

I would say do all the "basic" up grades,Intake,full exhaust, etc. and go 3.42s and the Eaton Posi. Thats what I did and could not be happier. Pulls nice and hard from a launch and is fine on the free way with OD.

 

i say 3.73s and widen your rpm band. you will tell a difference.

i have 3.73s in my 350 with 750 carb and as long as its tuned right you can get good gas mileage with your car. fuel injection can be a little over-rated. i get better gas mileage with my carburetor than when i had tpi

 

what trans are you running? I dont turn near that amount.

I have 3.73s and love them in my car. I wouldnt go any lower though.

 

It was a turbo350 out of an old truck .

 

so why did you tell somebody with a 700r4, that they would be turning 3500 rpms at 60 with 3.73s?

Keep apples with apples

 

my car never turns 3500 unless I'm doing about 75-80

 

He never said he had a 700r4? Besides that IMO 3.73s is to much for automatic. Cheers.

 

my tranny is stock to the lo3

 

Then it's a 700r4, Sorry i was basing my assumption on a Turbo350 transmission and forgot overdrive on the 700r4, which i still think 3.73 gears is overkill for a stock auto lo3.

 

It seems like gears could be hit or miss without having it on a dyno. I just bought an 89 Iroc that's pretty heavily modded in the engine, but nothing done to the gears or trans. It's a 5-speed tho, so with the engine mods would it be logical to go to a 3.73? I guess I've already answered my own question though: put it on the dyno.

 

So your gonna buy like 10 sets of gears, remove and install them, and try them all out on the dyno just to see which one performs better? HAHA

Base your gear ratio on how you drive. If your a street strip car, hands down 3.73 is the best gear combo. If you want a little more @$$ than stock I'd go 3.42s or something. If I wasn't running nitrous I'd have 4.10s. I just want to go fast. And looking for lower e.t

p.s a lot of 5 speeds came out with 3.73s stock you will probably want to check on that

 

Haha, no, I didn't mean keep putting different ones in, I just meant find out how much power it's got so you could pick the right ones. Maybe I'm not understanding exactly how a dyno works though, it should put out the same horsepower no matter how it's geared is what I'm thinking. =)

Like you, I just want to go fast. The engine has like every power mod you can do, and I would like to be able to take advantage of that. ( I bought it that way)

 

THe dyno doesn't care what the gearing is; it relates power, to engine RPM. Pays no attention to wheel speed, as far as its power calculations are concerned.

It will tell you, in what RPM range the engine makes the best power. You selct gears, to make the engine run in some given RPM range. THerefore the dyno tells you EXACTLY what you need to know.

Besides, it's always fun to hear your car wind out at full throttle.

 

That's what I was wondering. Thanks!