hey everyone i just got a 02 ls1 rear end with 373 gears.. i need the rear end because my nine bolt is about to take a dump and i want the better brakes so its a plus no matter what... i was wondering would that gear ratio be ok with the FIRST TPI. this intake breathes above stock tpi capabilities and flows alot more... i dont like going over 75mph anyways and i dont take it down to the track so i wouldnt be seeing those 70+mph... i just want a really strong bottom and midrange monster and a super strong take off with ease with quick 0-60 second times...... really i can care less about losing top end speed because i didnt build the car to go much over 80mph anyway.. i feel that the 3.27 gears that i have is just feels a little lazy and going in four gear brings the rpms way down which i hate that.... its behind a 355 FIRST TPI with a gm hotcam, 700r4 probuilt with a corvette stall..... i think i would like it... what do you guys think.....

 

you do know that 4th Gen diff has a longer housing... is one inch wider on each side...
your tires will... end up 1/4 inch or so beyond the wheel well... I modified mine when i installed my c-clip eliminator.... the diff is way better then the POS Australian 9 Bolt
3:73's are not to radical... your RPM roughly 500 - 600 rpm higher then your 3.27 @ 75 MPH you should be at 3,700 RPM's in 3rd

 

yes i know that the wheels will stick out some... my car is lowered as well so it should look really good..... im bout tired of the nine bolt because there is basically no aftermarket for them and are expensive to find parts and those tiny brakes and 26 spline axles just suck.... with the ls1 rear end i get lower miled rear and MUCH better brakes.. i hear that the ls1 rear ends got the torsen... i was wondering would i feel a big difference down low with the 3.73 gears over the 3.27.... would the 3.73 gears be good for around the down...

 

All 9-bolts are 28 spline. The LS1 rear is equipped with the Torsen. IIRC, 3.73's weren't OE gears in the LS1.

JamesC

 

This Guy had 3 73 professionally installed in his car a few years ago... I'm just wondering would 373 be fun on the street with the first tpi and 700r4 with a hotcam

 

Yes. For what you want they will work fine. Had a friend with a 383, stock TPI, rebuilt tranny, with 373 gears. It was a beast to about 100 mph. High 12 sec car BTW.

 

I agree I think for around town It will be good

 

thats good... i basically want to be untouchable from 0 to 90 max..... thats where i like my power range to fall at..anything above that is pointless to me and i can careless about power up that high.... thats why i didnt want to use my miniram... i instead sold it and bought the first intake, a great intake where i feel is best for street use..... 3.27 just felt boring to me..

 

now i guess with 373's i wont need such a high stall... i had a ten inch 3000 stall but it gernaded on me so i went back to the vette stall.... i was thinking about 2400-2600 9.5 inch stall would be perfect

 

yup but on dig's you might just sit and spin....im thinking of doing 3.42's

 

i dont mind that..... i spin now.... i just half throttle it then when im actually moving floor it..... i have surpised many guys like that.... i surpised a ls2 gto from a dig about two weeks ago... i launched liked a rocket and it took him a good while to finally catch me but by the time he caught up to me i had already stepped on the brakes because i was over 70mph.... so i gave the ls2 a run for its money and thats 3.27 gears and edelbrock base and stock runners.... i wondering how much better it would be with the FIRST and 3.73 gears.... should be insane....

 

post vid's man woohoo

 

Whats the max speed in first gear? just curious...

 

Depends. Are you basing it on shift point, max RPMs, rev limiter, manual, auto? Tire size will have a slight affect too. Just taking a wild guess I would say around 25 mph at the most with 3.73s and a 700R4.

 

Im saying first gear 5000 - 5500 rpm on your 700r4. On my t5 with 3.42's i max out at about 25 mph, almost like a granny gear! I guess its more annoying with a manual than with an auto.

 

i have 3.73's with a modded TPI 5 speed tremec tko 600 i hit the shift light just before i pass the 1/4 mile in 4th gear, fun on the street

 

so with 3.73's 25.8 inch tire and a 700r4... where would my rpms be at when im driving 70mph......

 

https://www.thirdgen.org/forums/post...701-post5.html

slightly more due to 25.8 but not enough to notice much.

 

so will i still be able to cruise safely on the highway with my 700r4 and 3.73 gears.. thats the only thing im worried about.....

 

I don't think I've done much over 120mph with a 700-R4 with 26" tires and 3.73 gears. With a T5, I've gone 140.
You'll be fine.