Replaced the 25556 in 1980. Manufactured by American Bosch OR Prestolite in a 3" diameter. A few years later, replaced by the larger 4-1/2" diameter model using the same part number. This motor originally came with one positive post and grounded through the back mounting stud of the motor. In appoximately 1999, a dual post - one positive - one negative was introduced (Lester 10757). When using the newer Dual Post motor for replacement, you have to make sure the rest of the power pack is grounded. This is easily accomplised by installing a 16 guage jumper from the gound post of the motor to the mounting screws of the cover on the cable controlled units or to the back mounting bolt of the starter motor for all electric units.