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

318willrun said

While the MPG didn't have the gains we hoped for, the project was a success due to the part throttle response/added power. Also, the valves seals were bad which was the reason the hole project was even started in the first place are now replaced!

Click to expand...

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.