Ray,
I used the 508 with a Bud's Benz type compressor bracket. I beleieve the 505 is justa smaller package but will work equally as well. The Bud's type bracket can either be bought from bud's Benz or fabricated from 1/4" steel plate. Itis a flat metal plate that mounts across the front top of the engine--alternator stays in the normal place and the bracket attaches with several bolts in existing holes around the water pump. If you already have an a/c set up, all you need is a York to Sanden conversion plate which are available any number of auot a/c houses and on e-bay from time to time. Since I have a 230Sl that did not come with an a/c setup I could not go this route--not enough pulleys on the water pump/fan combo to make it work right. Good luck. My 508 is running R134A and runs reall cold, but you can get the Sanden's set for R12 if that's the way you wnat to go. If you make the conversion to R134, you really should change out your hoses and fittings for the high pressure ones and install a parallel flow high efficiency condensor available from the a/c suppliers.
George Des
