I have an 88 IROC, with a minor build 355. it has 10:1 compression, .500 lift cam, 1.6 rockers, 24 lb per hour injectors, small port job on the heads, and full exhaust. I have no idea how much power, i'd say 300 horsepower if im lucky. but as usual for TPI, it has a lot of torque.

i'm installing a 95 t56, with a 2.66 first gear, and .5 6th gear. and i'm not sure what gears to put. 3.73 is definately the smallest i want to go, but im not sure if i should go up to 4.10s or not.

people say 4.10s are great, but that just sounds like way too much gear. and that also sounds like terrible traction problems since i'm not planning on running slicks.

which should i go with? since it doesn't really have that much power, im thinking the 4.10s to make up for it.

what do you guys think?

 

4.10's are good, but with that tpi you'll burn through your powerband fast, really fast. I'm planning to get a short runner intake like a mini ram or something along those lines to give me some upper rpm horsepower. 4.10 are totally liveable around town and on the highway. I do a lot of highway driving at around 90 and I get 20+ mpg.

 

If you can't make up your mind go with 3.90's I still get 21 mpg with my setup!