i have the 2:77 gears in the 9 bolt now...i am getting the series 3 carier for it which one will be better for my car the 3:45"s or the 3:70's???will i notice a difference? and what will be noticed ???i have a 89 iroc z i had the engine rebuilt:.....it has a iski cam 257 hyd intake and 265 hyd exaust...is that ok? or is it to small? the engine was bored .30 and the heads were done with a 3'angle race...and minor bowl blended...has kieth black hypr pistons .....i have the 52 mm throttle body edelbrock headers(emisions legal) cat back from edelbrock.homemade ram air , screens cut ,k&n's,i have a external accel ignition coil,sub frames, tourque arm, control arms, 2:77 gears yuck, 160 thermostat, hyperteck street performer chip, fuel pressure regulator thanks matt

 

you should be ok with the 3.70s. either one you pick will give you a noticable difference. i think with your cam and your head work you will make enough power up top that you won't notice a fall off or not make enough power up top for the gears to hurt you. if you want to be safe you can get the 3.45s and you will be just as happy. plus get better gas mileage. it all depends on what you plan to do next and what you plan to use the car for.
if you have a higher redline (6k or so) the 3.70s will be good if you plan on doing other stuff in the future.
hope this helps
Andrew

 

3.45's is the best all around gear ratio for TPI engines.

------------------
1991 Camaro Z28
5.7L 5-Speed (originally 305)
317 RWHP, 418 RWTQ
13.23 @ 107.62 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Member: SoCal F-Bodies
-=ICON Motorsports=-

 

I'd go with the 3.45's also.

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89 RS

STILL Looking For:
An 87 IROC-Z28 350 TPI


[This message has been edited by IROCZTWENTYGR8 (edited August 16, 2001).]

 

Simple math......
3.45 with stock diameter tires/slicks
3.70 with 28" tall tires/slicks


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86 T/A 5.0 A4 & 2.77 gear
15.62 @ 86 mph
93 Civic 1.6L
13.5 @ 100 mph

 

why do you think a 3.45 gear is an all around better gear for TPI?



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1991 banditt2 #130 of 600
Project 350 TPI Banditt II
http://www.street-dawg-racing.cityslide.com
http://discussion-board.com/GreaterC...dyAssociation/
http://www.cincyspeed.com/