Another thing to consider is titling issues. Since most states used the engine number as the VIN prior to 56, if you change the engine the numbers on the title will not be on the truck any longer. As long as you own the vehicle or any title transfer is in-state you'll probably never have a problem. However if you sell the truck out of state and an inspection is required before the new owner can title it in their state, they will have a problem titling the truck without jumping through some hoops. Just something to keep in mind. Questions about titling issues caused by that very condition come up here a LOT.

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