Ihave an 05 ctd 6sp 373axle , 315/70/17s. airaid jr kit installed. I would like to get a little more power, but not spend a ton of cash, what would be the best way to get 25-50 more hp. I don't tow a lot, but I do drive a lot in the ozark mountains, any suggestions?

 

Get with Quad, you would do well with whatever you buy from him. I got the basic box for 150 ft lbs of torque and it got me 1-2 mpg and plenty of power (all I need). I triple tow, a fifth wheel and a boat, no problem and I never lack for power. Call Quad. He is an advertizer on this site and boxes are available in the DTR above. Quadzilla products.

 

For a slight increase in low end power (probably the 20hp or so you speak of) you could modify your tone ring and increase your timing a bit. It will cost you $0 and about 45 minutes of your time. Or if you want some real power, get something like Quadzilla's ZXT towing box, which will net about 65hp at the rear wheels.