Hi- I am new to the forum. I've been reading a lot to figure out what direction I should go in. I am looking at buying a 1996 International 4700 with a mechanical DT466 and an Allison at545. It has 200k miles on it and runs and drives very well. I can get this truck for $1500.00, so I think it's a good deal.

The problem is I plan to use this as a hauler for my 43 foot cigarette style boat which weighs about 16k on the trailer. On the test drive today its top speed is 56 mph at 2400 rpm. I will be using this truck to tow on the highway so 70mph is minimum necessity. What can I do to improve this? What gear ratio should I run? If I run a 3.56 will it have enough power up a grade? Any suggestion appreciated.

Jason