Last summer I swapped out the auto for a T5 in a 1990 L98. The car is far more fun now no regrets on the T5

The car still has the factory 3.23s and I am looking at 3.42 or a 3.73

has anyone else been down this path? Got any experiences to relate why use one vs the other gear? I would like the 3.73s for go fast and fun factor. The car is not a daily driver, is used on weekends only and sometimes to the track to test mods.

I have a set of GM 3.42s I picked up cheap. Wondering should I use the 3.42s or go to the 3.73s?

 

if it were my car i would go with the 3.73's. but just this weekend i came across a fourth gen axle with 3.42's cheap so im sticking with that for now. question? how does that t5 stand up to your 350? i got a t5 in right now with a 305 but am switching to a 350 soon. but i thought i would have to go to a t56 for the strength. does your t5 seem to handle the 350 well?

 

I hear you on the ex-4th gen gears thats where I got mine -- for $45

I found a set of GM 3.73s figured I might do them instead.

The 350/T5 survival rate is an age old question around this board. My current ride ('90 IROC) dynos at over 400 rwtq. My T5 is running as well as ever. No problems to date. I've raced at the track (1/4 mile and auto-x), beaten the turd out of it (half expecting it to grenade) and never had a serious problem. If it did blow up I suppose I might try a T-56 but hey, they have problems too. Probably try the Atrso kit before a T56...

If you decide to go with more power to the T5 I recommend the following:

- get a WC unit that is in good shape, preferably rebuilt from a quality shop
- spend some money on high end bolts bellhousing to block and be sure they get torqued down properly
- get a high end clutch and pressure plate and have them balanced to the flywheel
- use royal purple in the tranny
- use polyurethane bushings for tranny and torque arm mount (!!!)
- get a hi end bolt for the torque arm mount to T5 tranny, I got one an extra 1/4 inch longer so it seats deeper and does not pull out so easily

Do all the above before you build additional engine torque. Classic cause for T5 demise (or any other tranny for that matter) is building extra power at the engine with zero budget to the tranny and rear end.

my .02 cents worth

 

I would go for 3.73

you wont feel hardly anything going to 3.42s

I swapped from 3.42 to 3.73 and from the seat of the pants gauge, I can almost tell a difference, but nothing worthwhile.