because i bought the motor used with 170K on it, not knowing the past history of the truck life, i'd prefer to start with a good and strong foundation before i begin to add fuel and hp to the motor incase there could be some kind of internal weak part that could cause more damage once i get the top end built.
I will be doing a compression test soon, just to make sure the numbers check out ok. The most hp i'm going to have is 550, but i'm going to be working with the truck 7 days a week on our farm, so i need to make sure its going to hold up to the demands.
The rebuild may not be necesary, but since it's out and easy to access, i'd rather spend the money before i just throw parts at it in hopes it holds