4:77's & 35's...some stats...

[Ldub]

Since getting my 4:77's & locker finally wrenched into the machine, I have had to re-calibrate all the associated numbers so that I can evaluate changes in mileage, odometer etc.

First, I borrowed a GPS unit from my Boss & put a small dot on the lens of the speedo corresponding to 55-60-65-70 & 75 mph.

OK, now I know how fast I'm really going.

Next, I took a little 30 mile cruise, while my co-pilot, Hunny Girl, wrote down the beginning & ending mile markers, & the corresponding trip odo values.

Then, crunched the numbers & came up with nearly 7% (6.94) margin of error.

My old margin of error, figured the same way, was about 16% with the stock (4:30) gearing.

My current rpm @75 mph is 2800.

I will be updating this with my findings regarding mpg in the future, but my initial guess is that my mileage is getting better. As the fuel ga is moving to the left @ a slower rate @ previously known mileage values...
Also, while maintaining a cruising velocity of 75 mph, I am experiencing neutral intake pressures, sometimes even slight vacuum, where before at the same speed, I was always under 3-4 psi boost. That's gotta help.

For those trying to make sense of these convoluted calculations:

The mileage on the trip odo will be multiplied by .07, that number is added to the miles on the trip odo, then that total (actual miles driven) is divided by the number of gallons used.