Just bought a 26' cat with a 496 h.o.. It has Dana headers and the water pressure tube is lying in the back unconnected. cant find where to hook it up. Can anyone help? Dont know if I can just hook up to one of the plugged ports on the header or not. I'm used to working on merc outboards.

Pressure of the water in the header really won't tell you anything. It needs to hook into the the water side of the heat exchanger somewhere.

best place to take WP is on the front of the intake,,right at the thermo or right below if room, u can drill & tab a fitting right there, i think . Some manifolds u cant tho.

It should plug into a quick connector on the sea pump

x2