I would like to change the gears i have currently. Right now i have a 2.75 rear end and i didn't think i was going to pull my boat out of the water last weekend. If i still want to maintain a good 70mph on the highway and yet pull the boat of the water what should i go to? I have a C6 with 235/75R15 tires.

 

I would probably go with 3.25 gears without an overdrive tranny. My F-150 has 3.55 gears and it spins about 3000 RPMs at 70 without overdrive.

 

it depends on what your poweband is, i know my motor isn't happy below 2800rpms and makes no power, i should have gone with 4.88 gears. I have 3.82 gears in my t-bird which has a c6 and an fe that isn't happy under 2500rpms so it works out. your gear set also depends on what size stall you are running in your converter. you want your cruising rpm to be above the converter stall rpm so you don't overheat and kill your trans unless you have a lockup converter or a 2peice input shaft like an aod. go to google and type in gear ratio calculators, then play around with gear ratios with your current tire size and trans gears. get an idea of what rpm you want at 60mph and choose gears from there.

 

The truck has a 351M C6 tranny both just rebuilt. Tires 235/75R15
The boat is fairly light, it's only 18'6" in length fiberglass, so it's not a big boat. It just really struggles when i'm pulling it.