So I have a 302 with a e4od and the rear end is a limited slip with 3.55 gears from the factory. I've topped the truck out at 101 as my bench mark top speed. All I have is a exhaust- cut 2nd cat ran 3" exhaust into flowmaster super 10 and dumped under the bed. My question is if I switched to 4.10s what would I see in improvements? How much top speed would I lose? How much would it affect my gas mileage?- get about 11 now At cruising speed- 65-70 I'm at 1800-2100 rpm. Would I notice a difference between 3.55 and 4.10?
You'll be fine speed wise, acceleration will improve, mpg will be better in town and maybe worse on the highway. Keep it under 70 and you'll be golden sent from my igloo
Like when I went to the 1/4 mile I got a 17.1 at 79.89 mph. With the gear change could I possibly even have that speed increase?
For the 1/4mi your speed will probably increase since your acceleration will be greater. I've had mine with 4.10s to 118mph and wasn't against the redline, just ran out of power. When you got it to 100, was that redline or lack of power? Here's a decent calculator. http://www.fordfullsize.com/forum/f79/transmission-questions-opinions-10370/index2.html 4.10s, 65mph, 30" Tire = 2984rpm 3.55, 65mph, 30" Tire = 2584rpm ( With a 1:1 trans, not overdrive)
