Fuel Economy and diff ratio

[Valencia]

Id be looking at a 2.78 ratio for long trips

[utevanwgn]

I thought a 2.78 would improve fuel economy when my Q was 253 powered so I changed it from a 3.08 and it decreased fuel economy .
So I measured manifold vacuum at 100k and then put the 3.08 back in and measured manifold vacuum again and found I had hire vacuum with the 3.08.
Make of this what you will but I took it to mean that my poor little 253 was lugging its guts out pushing a 2.78 and was much happier revving higher with the 3.08 and not working as hard.

[XX7SANDMN]

vs 5lt turbo 700 easy to buy easy to fit better fuel economy and cruise all day with a 2.78 or 2.60 and cheap as converstion if you can find a donor car