Hi

First, I have trans-am 91 with lb9 stock (205 hp) with 5 speed and 3.08 gear posi. I remove my cat and this is the only modification i have made and i want to know approximatly the time and mph on 1/4 mile run.

Finally, will i see difference if i change rear gear for 3.42 0r 3.73 on 1/4 mile? Which one do you suggest to me? I want acceleration more than top speed.

Hey bud, the best way to find out is to take to the track!! Most tracks have a great friday night grudge program.
Yes, you will see a difference. How much, I don't know. But I guarantee there will be a difference.

I am living in canada and this is winter now!

I have just buying the car and i would like to know now the time on 1/4 approx.

low 15s, maybe 15 flat, at approx 89-93MPH is my guess.

------------------
91 Trans Am WS6
Bright White
5.0 TPI auto
Flowmaster 3" 2 chamber catback
Trans Go shiftkit
2000 stall converter

Built on Wednesday

This time, is it with 3.08 or 3.42??? How can expect to save second with 3.42 or 3.73 gear? Will i gain mph?

up

You will probably run low 15's maybe a fluke 14.9. If i were you i would go with 3.73 gears and this will take off about .3 tenths in the 1/4 mile. Good luck

------------------
88 IROC-Z 305 TPI 5 speed
Performance Resource Chip, Flowmaster American Thunder cat back exhaust, B&M Ripper shifter, MSD coil, TB bypass, TPIS MAT relocation kit , TPIS 170* t-stat, Richmond 3.73 gears, March Power & Amp pullies, Home made Ram Air, Steve Spohn SFC's, TPIS AFPR, Ported plenum by Daniel Burk, Gutted cat
Best et: 14.338
Best mph: 96.97
Best 60': 2.106
http://hometown.aol.com/famioso15/johnnyiroc.html

thanks all

I would go with the 3.73s if you have the 5 speed, I am putting together a rear end for my car, and since its an auto, I went with the 3.42s.

------------------
1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End

Current Mods: LT4 Hot Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Hooker 3" Aerochamber Cat-Back System, Performance Resource Chip, Accel Ignition Coil, Cap, Rotor, 8.8mm Wires, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET (w/o LT4 cam): 14.32 @ 97.7mph
(corrected for elevation)

7.5" 10 Bolt with 3.42s soon to come!

Salut mon ami Stallone...j'imagine que tu parle francais?

Napierville ouvre d'ici 3 mois...un peu de patience. Rien et mieux qu'un "time slip"

Just speaking a little french to someone else besides me in Quebec...

As for how fast, it's hard to tell. Depends on the state of tune of the car. I would imagine 15.0-15.3 or abouts on a well tunes stock 305. But they only way to know for sure is the track. I once had '78 TA that I bought all modified with Ram Air IV heads, headers, 10" torque converter, 3.73...all kinds. We thought the thing would run 11s...took it to the track and it ran a best of 13.3 at 99 mph. Removed the edelbrock torker intake and dropped on a early pontiac intake that night. The next day at the track ran 12.7 at 106 mph. I swear it felt like 11s on the street but only the track doesn't lie



------------------
89 GTA 350 T-Tops White/Grey----Looking for a little more performance than stock!

Merci beaucoup de ta réponse, j'ai hate d'un bon petit quart de mille..Selon toi, suis-je mieux avec 3.42 ou 3.73??? Vais-je le regretter (3.73) p/r à la consommation d'essence!!!!

p.s. sorry for the english man, i would like to practice my french!!!! hahahahahha

------------------
trans-am 91 3.08 posi 5.0 lb9 5 speed stock

3.42...Building a car is whole thing...a good balance of everything is what makes a car fast and enjoyable. 3.73 are fine if you have overdrive, but without an overdrive I would run 3.42...

If all you want is quarter mile accelaration then you need to calculate what speed you want to finish the 1/4 in and then figure out what gear ratio and tire size will do that in top gear 1:1 close to redline. Then that's the gear you need...

example 110 Mph for 1/4 mile
engine works between 2500 - 5000 rpm
28" tall tire
you would need around a 3:73 - 3.90 gear ratio



------------------
89 GTA 350 T-Tops White/Grey----Looking for a little more performance than stock!

I am currently running consecutive 9.6's @ 73mph (1/8 mile) with a 3.23 open rear end and the mods listed below. I'm considering putting a 2500 stall and 3.73 posi's. I was wondering if these would be the next most beneficial mods or should I go with some headers or porting the plenum next?

------------------
86 TPI 305 Iroc-Z
700R4 (rebuilt)
Accel HEI SuperCoil
Flowmaster
K&N Filters
Comp Cams H268 218@.050 454/454

I am not sure which will be "most" beneficial but certainly when you get the exhaust, 2500 stall and gears the sum of the parts will be greater than the parts. as for porting the plenum...i am not a huge fan of porting parts without previous experience and a flow bench to test. Some clean up do deburr any casting marks and gasket matching would as far as I would go but even if you don't do that the exhaust, higher stall and gears will really wake up your car!

------------------
89 GTA 350 T-Tops White/Grey----Looking for a little more performance than stock!