Well I bought this '91(see sig) and have been tinkering with it nd eventually want to either a 350 with tons of goodies(prob. the 350 RamJet crate motor, seems it would be wiser/cheaper) or(more likely) a mild 383 setup, with the Holley StealthRam setup.

So I just got the rear end redone, with 3.73's and I like it. I started with 2.73's. A lot of people told me that 3.42's would be more effective for the TPI's powerband but I dont plan to keep the TPI on there much longer, I want to move the powerband to the upper RPMs anyways.

So if any of you out there are thinking about 3.42s or 3.73, but heard the 3.73s are too much for the TPI....that may be right but I cant see there being much difference between 3.73 and 3.42. If your keeping the TPI, yes, then go with 3.42's if you are concerned enough. But if you are planning on ever swapping out the TPI for a converted LT1 intake or HSR or MiniRam....the 3.73's should be perfect for an automatic unless you want a tad better mileage on the freeway and a tad better traction out of the hole.(then 3.42's if you want that)

So what Im trying to say is 3.73's are fine for a TPI car..especially the 305 like mine. It might not be perfect, but if you have future plans that include swapping out the TPI for the HSR, MiniRam or LT1 intake...then you would probably be better off with the 3.73s in the long run..unless you want to be stuck with the choice of either keeping the 3.42s forever or paying to swap up to 3.73 or higher when your car really could use it.

The reason I posted this is I have soooo many friends/relatives/redneck acquaintances that tell me "Nooooo, dont put any rear end gears on a TPI....it will be actually SLOWER"

Which I always though was BS. the car is faster in every way...highway, city, from a dig, roll, whatever. Sure the 3.42's would have been better for a stock TPI but why in the world would I put gears on it if I plan to keep it stock? Of course, I am going to mod it and later down the road I will wish I had 3.73s and not 3.42s, since its the same cost. Sure, from now until the time I get the TPI off of there it will have been better to have 3.42s but I can deal with that till I get the HSR or RamJet or whatever I get...(it wont be TPI whatever I do....I prefer higher-rpm power...its more fun, even though driveability suffers)

Thanks for reading...now Im going to go fix my speedometer...screw knowing how fast Im going....Im not worried about that....it now reads about 1500 miles for every 1000 I drive...thats gotts be fixed!

-Chris

Sidenote: Which reminds me.....WHEN IS GM GOING TO MAKE 5 or 6 SPEED AUTO FOR THE LSx VEHICLES? Ford did it for the stang and everything else they make will probably follow. A 6 speed auto swapped into a 4th gen with 4.11's would be killer!

 

Try it with 4.10s!!!

I just swapped out the stock 2.73s in my 92 Camaro with some 4.10s. Probably not an ideal gear ratio but I had them laying around so that's what I put in.

I ditched the whole FI system on my car in favor of a carb, but the trans is still stock (700R-4 automatic). 1st gear disappears in a right quick hurry. But MAN does it get into the power band quick! 20 feet down the road and you're into the "beefy" part of the torque curve.....

IF YOU HAVE THE TRACTION TO LAY IT DOWN. Which I do in this case (mild engine, plenty of traction). If you are traction-limited throughout 1st gear then steeper gears don't help do much but make more smoke off the line.

 

i wish i would have went with 4.10's or more.... 3.73's even with a miniram wasn't much.

 

what does swapping to 3.73's or 4.10's do to your fuel economy?? dramtically decrease it or what??

 

Well since before they were 2.73's...yes! Before the swap my 91 Z would get BETTER mileage than my '03 Altima 2.5...yep a huge 2.5L of displacement wasted more gas than my 305. Why? Dunno. Its been like that since new. It also got similar mileage to my '96 Ford Contour, only mrginally less when you consider that when floored the Contour would just buzz and slowly pull away, but with the Camaro it gets up and goes somewhere.

Now I get quite a bit less mileage but I dont care: now I gotta drive the Altima for mileage, not the Camaro(the way its supposed to be dammit )

 

I would have went with the 4.10s but I wanted this one to be a tad more streetable(plus it would have sucked with TPI while Im waiting on the rest to get done swapping out the TPI), besides, I have the '99 for that! Plus its nothin a little gigglegas wont fix Just push the darn button when you want to go from street to strip.

 

auto or stick?

I've never had an auto with 4.10s but I would think the miniram would be PERFECT for a 5 speed with them.

If I ever get my '84 back up to snuff(its been in storage for about 5 years...its has 3.73s also) it will be an auto/4.10 combo...possibly an LSx/4L60E setup.

I kindof want a truck again.....had an '01 Sierra 5.3L auto(3.73s as well). If I do then that will become my new focus and would probably be 3.73s as well. 4.10s on a truck on the freeway? nah. gimme a Camaro though and I'll run 4.56s down the mother all day.

I guess it just depends on your lifestyle and if the cars is your primarly vehicle.

In the 3.73s on a TPI case, I would recommend them to ANYONE who isnt an absolute penny-pincher and HAS to have better mileage(3.08, 3.23, whatever)

I will say this, I dont see why anyone would EVER willingly choose to have 2.73s(Aside from the top speed guys). It was a pain to drive the car with those on there. Not enough get-up-and-go and it makes the pedal feel h-e-a-v-y. Now its like a whole new car.

I thought the car was just slow and there was nothing to do about it aside from more power. Its my first run-in with 2.73s so I didnt know just how bad the gears were holding it back. Even on the freeway: No Contest. 3.73s hands down. 3.42s would be perfect for the freeway cruiser, but 3.73s are an excellent compromise between mileage, acceleration, driveability, top speed(now about 140 Im guessing..the speedo only goes to 120) and traction(Makes it a tad easier to hook than 4.10s)

Its not like I've never had 3.73's, quite the opposite, Ive never had much of anything else aside from the 99(4.11) and the old 91 gears(2.73)
This will be my 5th car with 3.73s, but it never ceases to amaze me how much of a difference it makes.

Ok I'll shut up...gonna go browse some other threads, unless someone has already posted here...

 

depends but i lost a considerable amount....mainly because of the obvious with my rpm's up higher when cruising.

 

We put 3.42s in my Cousins 86 350 TPI Auto (originally 305 of cource) and it really woke that car up big time, my freind put 3.73s in his car and it is almost perfect dragging, He has a 383 with Bowtie iron heads and ported base and plenum with large tube runners, and a big T/B (monoblade). When he first got the car it of course had a 305 TPI in it with 2.77 rear gears. Best times were mid 15s. he added 3.23s and gained a half second. He then did exhaust and other goodies and wittled to the mid 14s. he then added 3.73s and ran high 13s. With the 383 and the 3.73 he runs high 12s with stock suspension and street tires.