I have a 1988 four winns with a 5.7 litre omc motor that just took a dump and i am looking to replace it but before i go dropping a ton of money into a remanufactured motor there is a 5.7 litre merc motor for a fraction of the cost of the remanufactured one.How much work would it take to switch it over the guy selling the motor says it will bolt right up because they both are chevy 5.7 litres and both have 1 piece rear mains and if he is right is there anything else i have to change to make the switch? any and all information is greatly needed and appreciated