[JP Noonan]

Lugging the motor is bad, especialy on a bus. A lot of people do it thinking the sooner they get into a higher gear the better the MPG. Unfortunatley the down side is it bends the crank!

I don't know about "compression hieght" I worked in a machine shop, maybe I'm daft (well, yes I am daft, but I digress) or we used different terminology. Do you mean "deck height"? In that case it is probably the same between motors, and yes it has a huge impact on CR. On any motor, but particularly on a air cooled VW, check the deck height of each cylinder, also cc each combustion chamber. Then figure out if the combustion chambers need to be grinded down to match with in a certain tolerance, and what base shims are needed to match all the deck heights (note: Bob Hoover contends that it is important to only use ONE BASE SHIM PER CYLINDER to avoid leaks. i.e. if the shim required is .060" use a .060" shim NOT two .030" shims or the motor will leak at the base) There are many sorces for recomended deck height and the formula for CR...I can't seem to find any of mine right now (haven't seen my Lash manual in about 6 months, must have put it in a safe place). Lower than 7.5:1 is a dog, above 8:5-9:1 is a problem on street gas.

Finding deck hieght is pretty cheap/simple. Torque down the cylinder with some sockets or washers instead of the head, then use a staight edge and feeler gauge. Combustion chamber volume involes a "burrette" (remember titrating acids in high school?) and thoses are an expensive one use in a liftime type of thing.