Quote: whats your mileage without using the overdrive?
You claim 22mpg??? i find that very hard to believe. not at 70. not at 55mph. maybe at 30 mph. even with your aerodynamic nose.
At .64 od, that 4.10 looks like a 2.62 gear. there was never a 440 6 pack Ive ever seen that got close to that mileage with a 2.76. Maybe 15 mpg at best with a light foot and tiny tiny cam. so you'd have to drive it like a baby even with your mileage master cam
factory cars with 3.23 got 13mpg at best.
Stick some meat under those lobes and your down around 10 mpg.
as for running 140, you run your car on a roundy round track. So besides you, there are probably 3 other guys on here that do that for speed. the rest of them want the overdrive for mileage or for cruising on the freeway.
What I am saying is that the milage difference from turning 3600 rpm to 2300 on the freeway is probably, at the most, 5 mpg. most of these cars get 2500 miles a year MAX due to insurance. and even then, most of that mileage is playing the streets. I wouldnt see any benefit in an od. Im not a power tour guy.
I am running a TKO (Keisler), 440-6(e-brock heads and Huges 535/515 cam), 3.91 cogs, 26" tall rear rubber. I religiously got over 20mpg driving from Chicago to St. Louis to MMW. 24MPG was the high. Made that run three times and was cruising at about 2200rpm at 69-72mph. Just as a reference for the MPG club.
I am running a TKO (Keisler), 440-6(e-brock heads and Huges 535/515 cam), 3.91 cogs, 26" tall rear rubber. I religiously got over 20mpg driving from Chicago to St. Louis to MMW. 24MPG was the high. Made that run three times and was cruising at about 2200rpm at 69-72mph. Just as a reference for the MPG club. 
