i know its supposed to be in the drivetrain board but i was wondering from fellow tbi people with the lo3 what kind of difference i would notice when i put on my recently aquired 3.42's and posi from slp...
thanks
Shawn

 

You'll love it. The car will pull harder because you're getting into your power band quicker.

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West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

At what point does the gear ratio get too high with the LO3 and 700R4? Would 3.73s be a better choice than 3.42s? Would 4.10s be too steep? I wanna get new gears too!

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'68 Camaro - Vortec 350
'91 Camaro RS - 305 TBI

 

When I switched from the open 2.73's to my SLP take-off posi with GM 3.42's, and I put on some Nitto drag radials I dropped my 60ft times from 2.5.-2.4's to 2.0-1.9's. Which in turn dropped my et's from 14.7's to 14.4's.

You'll love them

Mike

 

Yeah, I had 2:73's, 3:73's and now 3:42's. I liked the 3:73's but I think the 3:42's are better for street/strip use. But u can use either if u want. Both are great gears.

------------------
Eric Natzke
91 Firebird 305 TBI
"It Ain't Stock"
http://members.aol.com/j007golden/91firebird.html
For info on certain parts or mods go to the site below
http://members.aol.com/j007golden/modeval.html

 

bhaaaa 3.42s are a womans gear but seriously i like 3.73s, it seems to be a good compromise between off the line and top end performance...

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1989 pontiac firebird
bright red exterior(just repainted)
grey interior
5 spd
305 TBI (stock)
WS.6 formula wheels
3.73 posi rear end
http://members.aol.com/j007golden/Mikey89.html
-------------------------
1985 trans am
factory bright yellow
4 wheel disks
16 inch wheels
305 TPI
power antenna and mirrors
t tops

 

I would go with the 3.42. 3.73 is a bit to high and would make you have a low top speed as well as an almost useless first gear (if you have a T-5). Some of the greatest sport cars in the world don't have anything higher than a 3.73.

z06 = 3.42
Viper = 3.38
BMW M5 = 3.39
Jaguar XKR = 3.06
Benz CLK55 AMG = 3.40

One of the highest I have seen (in a new car)is in the new BMW M3 which has a 3.62 but then again it has a 8000rpm redline.

 

The stock cam in a TBI starts to die around 4000 RPMs, so if you have too much gear you'll hit redline before you get to the end of the track. 3.42's are a good compromise. If you're gonna do a larger cam, intake, heads, etc, or you dont race at the track, get 3.73's then.

 

Where can i pick up the 3.42's and where can i take them to get installed.How much do they run for and what do i need to buy.I am a novice at this and recently bought my car 3 months ago and i am doing alot of research...THanxs guys

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1988 Trans am.......best 600 bucks ive ever spent...305 5.0 but will save my lunch money and every penny to swap for a 350 tpi in the coming two years

 

ok i never understand when people say this. 3.73s make u hit redline faster, that is true but when u hit red line thats when u shift. I thought u wanted a motor to rev out fast. the faster u rev it the faster u need to shift and once u can get that down ur good.


BTW all the new cars that shifty mentioned would have lower gears. economy and mileage is somewhat on thier minds. makes for good sales...

 

That is true but all of those cars still have neer 400hp each. Anyone who can afford those isn't really gonna be concerned with gas mileage. The vette gets the best milage because of the large 6th gear, but the others are only high teens on the highway. I don't know many thirdgens with 400hp that get mileage like that. 3.73's would be good if you swaped a t-56 in to keep revs down when crusin on the highway. For cars that have a high redline high gears are great because it keeps the motor at its peak. However us TBI guys have a very low redline so to high of a gear would surpass our peak power point too fast and will not allow us to take advantage of all that low end torque. That is why I think a 3.42 would be a nice comprimise. Especially if future mods will give me faster engine speeds. I know that the gears in my T-5 are ok but first is way way way to short. A bunch of pricey mods (manifold, new fuel system, cam, headers etc...) will give me a higher reving engine that will have a larger powerband, hence where the 3.42's come in great. The best setup is to grab a shift into second between 50 and 60 mph. The fastest street cars in the world now seem to shift there. And car speeds are faster than ever. Engineering is amazing. That is how most new highperformance cars are engineered all of which run to 60 between 3.8 and 5.2 seconds. I want to try to match similar setups in my car so that I can get the same acceleration. Some cars get slow times because each shift costs about .1-.2 (depending on person but I have read those are the numbers) seconds. So if you can get a rearend and a tranny that match to keep your motor in its flat power range you are golden Just a thought. Then again this knowledge is from research and not from first hand experience. Not many street cars have gears that high.

 

Upick autoparts in medley. Several thirdgens on the lot, pop the cover off and look at the ring gear for the pinion to ring tooth ratio, divide, if you come up with 3.42 its a 3.42 rear if you come up with 3.73 i think you can figure out the rest
they want 55 dollars for the entire rear
take some decent tools and a friend, take the rear
come home, and put it in your car. Get a powertrax locker down the road or a posi carrier (more work though)

 

you can get the gears from camaroz28.co thats where i got mine from a 4th gen guy who installed 3.73's instead.they are in perfect shape and i paid 40 bills for them i bought my slp posi earlier today and now i need to buy my install kit. the slp posi cost 99 bills and the install kit cost another 45 to 99 bills lucky i have a friend to install them for free cause that is the expensive part..i use the 3.42's because i am moving to phoenix and i am going to be doing alot of freeway driving.i like top end too..
Shawn
getting ready for my first big mod and f*cking happy...

[This message has been edited by pimpintheRS (edited March 20, 2001).]

 

Um, I highly DO NOT recommend getting a used posi. Buying any internal parts used is just a bad idea. You have no idea what kind of wear and tear they went thru and how long they will last in ur car. With the money u spend for a new one, you know what u are getting and it has a warrenty.

------------------
Eric Natzke
91 Firebird 305 TBI
"It Ain't Stock"
http://members.aol.com/j007golden/91firebird.html
For info on certain parts or mods go to the site below
http://members.aol.com/j007golden/modeval.html

 

to late already paid for.. so i should've bought my gears new too since they are used ? 40 for gears is much better the 180 and up for new ones. Just cause its new doesnt mean sh*t.. not all of us have alot of money i about to move to phoenix and i am just trying to make my car a lil faster since i will be moving to a town with a lot more riceburners... slp take off posi 99.95 the rest upwards of 299.... i think i want to save a lil money...
Shawn

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91 RS 5.0 TBI
14x3 open element
160*stat... didnt do anything made my car run a lil cooler
msd coil and taylor wires ...not noticed
with split fire plugs... which suck
removed rear hood seal.. runs much cooler i liked

coming soon 3.42's with slp posi.. my first big mod!!!

Clarion cd player 2 planet audio 6x9's 2 lanzar tweeters and one MTX 10" sub in a bandpass all running off 2 separate 200w amps

 

Ok, let me explain it this way. I'm going to simplify it because I dont have the exact values. You have a 3 speed automatic with overdrive (700R4), with 3.73 gears in the rear end. The starting light turns green and you launch. With the 700R4's steep first gear, you get about 60' out at 5000 rpms and you have to shift to second. Now in second gear, you get to just before the 1/8 mile at 5000 rpms, and you shift to third. In third, you get to 5000 rpms at 1150 feet. But the track is 1320 feet. Now you're out of rpm, you either keep going in third gear passed your redline, or you shift to fourth gear, overdrive, losing the torque multiplication. Your times might suffer because of that. If you shift at 4500 rpms, it'll be even worse.

But, if you have 3.42's, you dont hit redline as quick, so you can go thru the whole track and cross the finish line at redline, in your car's horsepower peak.

Does this make sense?

 

yes it makes complete sense. I was trying to explain that in my post. Anyways who cares about the quarter. I want to beat a ***** on the streets where everyone can watch. What are your chances of consistantly lining up against different cars on the track as opposed to on the street. Plus I don't want to lose on a highway drag because 3.73's will hit the speed limiter so soon. OUr TBI's might not be that fast compare to others that we race (ricers, v6 coupes, etc) but when I hit 60 mph is when I start to pull away and win.

 

i just want to get to 70 mph quickly.i got a 3.42 because i know this came with a 305 ho from the factory with a automatic. my car is now turning 2600 rpms at 60 and thats high enough.of course if i ever get a six speed...

 

If you got a six speed you would be sittin pretty.