Ford F150 conversion van, 410 rear, beefed up automatic transmission (extra clutch plates). I added an external engine oil cooler, and transmission cooler, which did a great job. I got the coolers from JC Whitney cheap!
The boat was a 210-Proline with a 150 Yamaha outboard, rigged for offshore fishing, carried 125 gallons of gas. Total package boat, motor, trailer, fuel, etc..., tipped the scales at just over 6,200 pounds. The van didn't even know the boat was back there.