410's and rpm?

[95MARK8LSC]

I was just wondering....can anyone with 410's tell me what the rpms run at at 80 mph in overdrive?

 

[Sierra3]

yes... i just drove from Fort Walton Beach Florida to Syracuse NY and back to Florida. I ran at about 80 with cruise controll on. It runs at 2500RPM stock rims with 245/50-16 Bridgestone Potenzas on. Get that tranny cooler put on too! i just had my fluid changed out and was amazed to find that the fluid was still bright reddish pink color after 3000 miles of constant beating to and from states. Absolutely no metal flakes on magnet either. This is a must to save tranny with 4;10's.

 

[TM]

I use this formula for finding RPMS:

RPM = (MPH / (Tire Radius / 168)) * Axle ratio * gear ratio

I made up a little Excel spreadsheet, and according to that formula, in OD (0.7 for a 4R70W) with stock-sized tires (225/60/16) with a 4.10 rear end, you should be turning 2897 RPM.

With the example above (same except for 245/50/16 tires), it predicts just over 3000 RPM. Maybe the formula is a little high, but I've found it to be pretty close with my stock '98 LSC (2310 @ 80mph).

[font color = blue]Tony - St. Louis, MO[/font]
1998 LSC - Toreador Red/Light Graphite
1987 Mustang GT - Oxford White hatchback

 

[GRAND_LS 400]

mine stock gets about 76MPH at 2000RPM with 245's/50/ZR16's

 

[Sierra3]

im not sure of the number of teeth, but we did switch out the speedo gear twice to get it close..im about 3 to 5 mph off still when shot by radar here compared to my speedo.

 

[Eli]

23 tooth, and its not perfect, but neither is stock.

 

[SQUIRELL]

I have 4:10's and checked it for you yesterday.
2500 RPM's @ 70MPH
3000 RPM's @ 80MPH
with 245-50-16's

 

[95MARK8LSC]

Thanks for the info. I was just wondering because I've heard that going with 373's is not too different from the 327's. It's just for future reference. I'm not really planning on doing it too soon. Maybe if I win some money.

 

[brentalan]

I was pretty happy with the 373s, but I came from 307s. With 373s I pull 2500 @ 75.

Brent

http://www.eden.rutgers.edu/~brenth/markviii/Brent's-Mark-VIII.jpg

 

[Leecon]

I've found that 3:73s are best for a combination of street/strip, driving, for me. I usually cruise at 80-85, above 3:73s I constantly feel like I need to shift up. I don't think you'll get much of an improvement in performance going from a 3:27 to a 3:55.