[JJR]

I would keep the 292 until it dies but I like inlines. I would give the 292 a good tune-up and maybe a can of Restore at the next oil change and run it. However, the 292 was noted as having great low end torque but was not known as a gas mileage queen so your desire for an overall 17 mpg may be hard to meet. Since you mention the truck needs other work, I would spend the money on other portions of the rebuild until you need to swap engines. You can do an engine swap anytime.