Hi !

FWIW  my -88 Vanagon with a 2.1 litre Volvo engine will run 90 mph ( on my speedometer ;-) ) without problems the max power output is a bit higher than the VBX ( 107hp /5250 rpm)
Comfortable speed however is about 55 mph....( 2.800 rpm)
Fuel economy - hard to tell, have been riding it for a couple of weeks only with small adjustments still to be made..............................

Calle