to make a long story short, I have a slipping 700r4 and I need to replace the tranny, I will be replacing it with a TH400.
With my 700r4 I was getting around 30mpg with a Holley Stealth Ram on an otherwise stock 350 with a good Megasquirt tune.
My question is how much will losing an overdrive gear affect my MPG?
If it makes an difference (and i know it will) I will be upgrading to a 427sbc, 210cc alum heads and a medium duration solid roller turbo cam.
Like i said before I have a Megasquirt with a Wideband O2 sensor, so I can run it fairly lean for improved mileage.
Mileage is very important to me because I NEED to drive it 2000 miles to get it to my new home. After I get it there, MPG is no longer important.
EDIT: I should mention that for the trip I am going to run a really tight convertor. Summit has a 1700-2100 stall Convertor for $99, hughes makes a "Fuel Mizer" TQ for $189, but I dont think that TQ will save me $89 worth of fuel compared to the summit. http://www.summitracing.com/parts/HUP-GM5FUEL/