All for .370 lift and under ........

mgoblue9798 said
Couple thoughts-

Did you lose compression doing the valve job- thicker head gasket or carbon cleaned off piston tops/head chambers?

If it winds up 1/2mpg better from 13.5 to 14 would be a 3.7% increase in fuel mileage. Not bad for a valve job and tune.

The aero of the van may well be the biggest limiting factor in getting much improvement in gas mileage.

You make a very good point..... 3.7% is a nice gain when looking at it that way. I should have gained compression because the heads were off before and they used a typical over the counter head gasket, and I did the same but cut the heads .030. I agree, the aerodynamics are killer on these year of vans