MM,

In the header for this thread you mention 'right' height control valve, did you mean 'correct' or right/curb side of the bus? Either way, the valve you have pictured here and on your web page are universal in that it can fit either the right (curb) or left (road) side. The center port is always the inlet/supply, the top port is always the exhaust and the bottom port is the delivery port. This valve has been used by Neway and other heavy duty air suspension manufacturers for years and is readily available throughout the US and Canada. If the valve is centered when installed via the little dowel supplied you should always be able to level without changing the adjustment nut.

On the Spartan chassis with IFS the alignment of the front end is controlled by the vehicle ride height - maybe on the Prevost too, but I don't know.

Here's a link to explain some of the alignment terms (caster,camber,toe in/out): http://www.ozebiz.com.au/racetech/theory/align.html