Questions about a 3.73 in a 3rd gen

[ruckusz28]

This is not a TPI motor. Gm Performance Parts 350 HO crate engine with a Holley 650.

[hoogiesngrinderz]

If you'd like I can calculate speed/rpm for each gear, that might help you decide what's the best. I'm leaning towards 3.42 for your setup.

[ruckusz28]

See, going from a 3.23 to a 3.42 just isn't worth it to me..

[Darren]

See, going from a 3.23 to a 3.42 just isn't worth it to me..

not even worth your time. You wouldn't notice it. 3.73 or nothing at all

[hoogiesngrinderz]

I don't want to be the ass here, not knowing exactly what trans Mike has, but here is the math.

Non WC T5
3.73 gear
1st - 12.49:1, 26" tire. 6000rpm in first gear is 37 mph
4.10 gear
1st - 13.735:1, 26" tire. 6000rpm in first gear is 34 mph

WC T5
3.73
1st - 11:1, 26" tire. 6000rpm in fist gear is 42 mph
4.10
1st - 12.095:1, 26" tire. 6000rpm in first gear is 38 mph

See the difference now? My WC T5 setup with 3.42 will puts me at 46 mph in first at 6000 rpm. I really depends on the power of the engine, and his mill seems like it would be pretty decent. 3.42 rear with his trans would put him at 40 mph (assuming it's 3.35 first gear ratio)

3.42 and a .73 overdrive would run 2500 rpm at 70 mph.

[ruckusz28]

Thanks for digging deep. No offense taken - the proof is in the math. I'm set on the 3.73's now. I don't often go on the freeway, but as long as i'm below 3 grand at 70mph I will survive. I'll just have to pad the wallet at the pump.

[Darren]

Thanks for digging deep. No offense taken - the proof is in the math. I'm set on the 3.73's now. I don't often go on the freeway, but as long as i'm below 3 grand at 70mph I will survive. I'll just have to pad the wallet at the pump.

I drive on the highway all the time (when my car runs ) and I have never even noticed a problem on the highway. It must be so minimal I dont even know what the RPM's are when I am cruising at 70 (although that is rare as well). 3.73 is your best bet for seat of the pants difference, I would bet you wouldnt notice a change from 3.23 to 3.42...

[hoogiesngrinderz]

His setup at 70mph will be just over 2600rpm with a 3.73. If he put in your transmission, and 3.73, he would be going 86 at the same rpm. Big difference in overdrive gearing.


I just hope you don't find first gear to be short. 2, 3, and 4 gears are almost the same ratios in all T5's (except v6)

[Darren]

His setup at 70mph will be just over 2600rpm with a 3.73. If he put in your transmission, and 3.73, he would be going 86 at the same rpm. Big difference in overdrive gearing.


I just hope you don't find first gear to be short. 2, 3, and 4 gears are almost the same ratios in all T5's (except v6)

Your not even sure what T5 he has tho... And there is no way I am doing 42MPH in 1st gear and who shifts a (stockish) 3rd gen at 6,000 RPM's?

[hoogiesngrinderz]

Your not even sure what T5 he has tho... And there is no way I am doing 42MPH in 1st gear and who shifts a (stockish) 3rd gen at 6,000 RPM's?

You're right. Given only details about other parts and how fast it travels at what rpm, I can only calculate his transmission gearing. If I had the casting number I wouldn't have to guess. By the way, I screwed up on the calculations...I added when I should have multiplied the gear ratios. I'll fix it.

He's got a carbed 350 crate motor, he can shift above 6k if he really wanted to

[ruckusz28]

I can Hardly hit 5k at wide open throttle. My Holley is jetted too high and bogs down when I get into the higher rpm range. I'm switching to an edelbrock 600 with a better intake come spring. Then we can get stupid and dust off the valves.

[hoogiesngrinderz]

I'm not a fan of the Edelbrock carbs, but am a fan of Italian tune ups