Originally Posted by AutoGear
theres more than one T5 ratio.
What did it come from? Amc, Iszuzu, S10, Camaro? 4, 6 or 8 cyl.
If you have the usual T5 hybrid conversion (V8 camaro guts and an S10 tailhousing), that has a 2.95 1st gear, which is plenty for 3.73s, let alone 4.11s
Find out what your first gear is and then pick your rear gear to match
If the trans is out of your truck, lock it in 1st gear and turn the input 10 times. Count the number of turns on the output. For example, if 10 turns on the input gives you 29 turns of the output, thats a 2.9 1st gear. Which I wouldn't recommend with a rear gear higher than 3.73. If you have a deeper 1st gear than that, you really should drop the axle ratio a little because those transmissions aren't that strong.
If you have an S-10 trans with a 4:1 1st gear and a set of 4.11s; thats 16:1 total reduction (4x4=16); which is like taking a Muncie or a TH350 and putting 7.00:1 gears in the axle. 1st gear will be useless, not peppy.
I don't think the shop has the transmission or rear end actually picked out yet. I'm assuming they're going with a T5 S-10 five speed transmission. There going to be putting a 55-58 era chevy posi rear end on it. I'm going to be running the original 15" wheels. Unfortunately, I'm not aware of what the first gear is.
I did talk again with some friends and decided to trust my mechanic with this one. I needed to get him paid as he's had it several days now and I kind of hate to question his judgement. I told him what I was wanting and he's basically saying this is correct from what he's researched. For me it's super complicated and since I'm making a significant investment, I was hoping there was maybe an easier way of figuring out the right rear end gearing for the job. I'm sure it will be fine. I'll have it back in a couple weeks or so, I'll let you know how it turns out.
Thanks for the information.