What can the learned members of this fine site tell me about the Jeep industrial engine that is used in my Hesse Hornet air compressor --Cylilnders 1 and 4 operate per usual, while 2 & 3 are the air compressor? Numbers, etc are as follows: Model IPU 4L ( I figure that is industrail power unit, 4 cy L head) Engine assembly ---913102 Serial number IVL 8860 and block Casting 908756. The approximaate date of build would be nice to know. Thanks