I found this (but you should check it to be sure):
The aircooled VW Beetle bell housing is a simple design. The motor is located with a centering ring that is 11.100 inches in diameter around the motor shaft. The outside diameter should be at least 12.400 inches but could be larger without interfering with anything. The motor shaft location can be used as the center for everything.
The top 2 bolt holes are located 4.328 inches above the horizontal centerline and 3.897 inches to either side of the vertical centerline (42 degrees to either side of the vertical centerline.) The bottom 2 bolt holes are located 4.117 inches below the horizontal centerline and 4.117 inches to either side of the vertical centerline. The 4 holes should be 7/16 inch in diameter.http://www.diyelectriccar.com/forums/sh ... 49403.html