[Mart]

I have a 3 speed in my 41 and 3.54 ears, with 6.50:16s. It runs nice at 45 and will go quicker if I want.

If your truck tops out at 45 there is something not right. It should go a lot quicker than that as standard.

I'd suggest you look at the motor first, it must be very short on power or there is something stopping it from revving through the range.

Mart.