I just got an Acra-Speed over the weekend and included were the instructions. I typed them out below:
Instructions:
There are two pointers. The pointer that is at the top of the engine when mounted on either 2 bolt or 3 bolt is the pointer you look at.
When installed on a three bolt cover, with the flat side perpendicular to the ground on the left, the pointer that is outside the edge is the pointer.
When installed on a two bolt cover, with the flat side at the 7:00 position down toward the ground, the pointer stamped into the base is the pointer you look at.
It would have originally come with a short adapter and long adapter on the back for the two lengths of cams. The short adaptor was used whenever the three hole mounted distributor was present. (with the exception of the cam being replaced) The long adaptor was used with the two hole mounted distributor. I'm guessing you only have the short adapter. They also had accessory rotating drums for 6 cyl Fords, 8 cyl fords and 12 cyl fords.
Installation of the Acra-Speed "CAM POSITION INDICATOR"
1. Determine the required long or short rear adaptor and install on the drive shaft of the “CAM POSITION INDICATOR.”
2. Install the "CAM POSITION INDICATOR" in place of the distributor in the position as required by the TWO or THREE hole mounting. Use bolts and loosely bolt the indicator to the cam gear cover using the proper holes in the back plate of the "CAM POSITION INDICATOR" Rotate the calibrated drum of the "CAM POSITION INDICATOR" in either direction while also slightly pushing on the cover plate until the offset drive key on the "CAM POSITION INDICATOR" engages the offset drive keyway in the gear end of the cam shaft. It is then necessary only to tighten the cap screws finger tight to put the "CAM POSITION INDICATOR" in service.
3) The TOP pointer on the "CAM POSITION INDICATOR" is now ready to indicate accurately and quickly the exact heel position of any cam on the cam shaft.
Two scales are provided on the drum for V type motors. One carries the letter "R" followed by a numeral, while the other scale employs the initial letter "L" followed by a numeral. The "R" index is readable from only the RIGHT side of the motor, while the "L" index is readable only from the LEFT side of the motor. When the "1R" index line on the drum is in line with the top pointer, the first or front valve on the RIGHT side of the motor is on the heel of the cam and in position for checking lifter to valve clearance.
The front valve on each side is indicated by "1R" or "1L" and the valves are numbered progressively toward the rear of the motor. WHEN ANY INDEX LINE ON THE DRUM IS AT THE POINTER, THE INDICATED VALVE IS ON THE HEEL POSITION OF THE CAM.
Rotation of the cam shaft while the pistons and crank shaft are in the motor must be handled by crank, wrench, fan belt or any available method. During rebuilding or complete overhaul jobs with the crank shaft and pistons removed, the cam shaft can be rotated by means of the drum on the "CAM POSITION INDICATOR"
Hope this helps!
- Oiler Elrod