74novacustom

Im running a 4L60E and 411 gears with 29in tall tires.

Down low im going to need track bite and slicks to hook.

On the freeway its not horrible, but id like it to be a little more calm. (Lower RPMS)

Im thinking of 373s, I know Trev is running 330s, how do you like those?

bitterman

I don't have things running yet but with the lentech I am planning on and the .67 overdrive gear with 4.10's and 275/60r15's on the back of my 68 Nova I should be about as seen below (depending on torque converter slippage):
50MPH ~1650
60MPH ~2000
70MPH ~2310
80MPH ~2640
90MPH ~2970
100MPH ~3300

Bruce

74novacustom

Hmmm i need to figure out why my tach doesnt work so i can refference it. Maybe its my exhaust that makes it sound too high

chrisfrost

iTrader: (8)

I used to have an 80' Z-28 with 275-50-15's on rear limited/posi 3.42 a built 700 using the check ball for convert control . locked up in 4th at 2500r's 85 mph . If You were going say 60 and nailed it , it would unlock n downshift to third and it would hit 100 in about 6 seconds . I liked those gears alot , oh ya the tires were 26"

bczee

iTrader: (12)

My Chevelle has a Viper T-56 and 4.10, Doing 65mph = 1850rpm, at 75-80mph. = 25mpg.. (tires are 275x40x17).

I bit more work on the streets. but hey. it fun to be shifting !!

Going with 3.73 for my Nova project that will have a 4L60E...

No problem !

gMAG

iTrader: (1)

tko600 5 sp here. 27 inch tires/3.70 rear/.063 OD/ 1900 @ 65mph & 2050 @ 70mph. Could've gone with a higher (number) rear gear. Haven't noticed what the higher speeds come in at, rpm-wise.
I like it alot!

Old Geezer

iTrader: (3)

60E, 3.50, lock up verter, 27.6" tires, = 60mph @ 2000

3pedals

iTrader: (3)

TKO 600 .64 OD gear, 4.56's in the diff, 28" tires. I am not 100% certain, but I think its at 2500 at 65mph. I had 4.10's in it before, and it reved a bit lower, 2200ish.
I prefer the 4.56's all around.
How tall you can gear it will depend at what rpm your cam is happy, and if you care about take off performance/60ft times/ET - I went 4.56 for ET
Barrett

gMAG

iTrader: (1)

Maybe you need a tach booster circuit??
Try this.. http://www.buyrcars.com/jag.htm
Scroll down near the bottom for explanation & photos
Courtesy of FastKat/Dave

S10xGN

iTrader: (11)

Same here, except 28" tire and 200R4 with a 9.5" 3600 L/U PI Vig. Showing 2000 @ 70 MPH

74novacustom

I will have to look into that some more, ive tried cutting just the blue wire and both the blue and brown wire on my tach and it still does nothing, it moves when i turn the ign on but thats it.

Pocket

iTrader: (22)

'80E with 3.55's and a 26" rear tire

About 2500 on the highway. Thinking of stepping down to 3.08's because I blow the tires off so easy

Nick V.

iTrader: (1)

i have 3.23s 245/40 17''s up front 275/35 18''s on the rear w/ fake zo6 rims

at 60-65 i think im somewhere between 1500-1800 rpms. My tachometer and speedometer are off so im guessing based off some scans ive done

bitterman

I have been using http://www.wallaceracing.com/gear-speed.php to mess around. The thing I like about this calculator is it gives you from 1000 to 8000 RPM in 500 RPM increments.

Worth playing around.

Bruce

chuckd71

iTrader: (23)

.67 OD with 3.73:1 and I think 28 inch tire. Seems fine but I want even more interstate cruisability so I'm picking up a t56 tomorrow. Double overdrive ftw.

rfrankb4

I have been playing around with this one
http://www.angelfire.com/fl/procrastination/rear.html does it sort of the opposite from the one you posted. you put in a target RPM and it gives MPH for different rear end ratios.

i have used it a fair bit recently. My build is nearing completion and with the original intention of 24.5" tall tires I changed my gear ratio from 4.11 down to 3.08 for good intrastate manners (LQ4 +4l80e). However, now the rear tire has changed to a 335/30/19 which is right at 27" tall and I am wishing I went with 3.42 gears or 3.55.

bitterman

Yeah, when I was planning my drive train I was looking at what RPM I should be crossing the 1/4 at. 4.30 or 4.56 would be better but since I will be driving the car about 1 hour to the track I stepped down to 4.10's as they were a better fit for what I believed I'd find acceptable for cruzing also. Truth be told I expect I won't be in overdrive till about 60 MPH but I did look at 50 and might be pushing it going ~1650 (was expecting so surging etc) But with the milder EPS cam I was spec'd I think I will be ok there now.

Pick a gear is all about compromises. Also up here in Canada the limit is 100 KPH or about 60 MPH on major highways and 80 KMH or 50 MPH on the rest till in town. I don't see cruzing much over 65MPH as the local enforcement will be sure to pull me over at bar minimum to look at the car.

Bruce

Smo's04Gto

iTrader: (8)

with my t56 430 gears 255/60's 2000 rpm @ 70 mph.

rp0029

iTrader: (1)

Does anyone regret putting too (numerically) high a rear gear in their car? I've got a 4l80e with 40R17s, 4l80e and 3.42s. I hope it will be a daily driver, but with the .75 OD gear, it will be doing 2500 at 75 mph. In my 2.73 rear '99 trans am w/ 4l60e it will do 75 at well below 2k, but still has serious *****. With 400rwhp I'm assuming that street tires would make first gear here completely useless, even with posi. I do drive on the highway every day. Is 3.42 a decent gear? What is the (numerically) lowest gear I can get in a 3 series carrier?

rfrankb4

Here are the gears that summit lists for a 3 series. There might be more but it would be difficult to find a DD set of gears that summit carries. I would bet that these are most of the available gears that would be hard enough for street driving.

3.08:1
3.42:1
3.55:1
3.73:1
3.90:1
4.10:1
4.56:1
4.88:1