I am building a hybrid 20r/22r engine it will have OS. valves in the head,the pistons are .020 over. My truck has a 32/36 weber and will have a header and free flow exhaust when I get done with the engine.I have searched but not alot of people are running 38" tires or bigger. My truck has 38's on it now. My truck will be driven on the street,but mostly in the mud it will soon have 5:29 gears. The two cams I am looking at are engnblder 261c or 268. Thanks for any help.