TheDon - Yes, I am in Sanford FL

Kerry - the 617 engine would be great (double the power, almost), but as I mentioned where would one find a low mileage one? Maybe that doesn't matter

This truck came with a rear axle ratio of 5.9, which limited speed to around 50 MPH (plus a lot of engine noise!). Changing to the 4:10 axle helped a little, I can no go around 60, or even 70 downhill. But the engine just runs out of steam for the load it is carrying, hence the need for more power