I have had my boat for a couple years. bbc panther logs. put a new carter comp. carb and hei on it. took it out sunday andwhen you get it off idle there is white smoke everywhere at idle is fine. both sides of exhaust. Oil isnt over filled, oil is clean. I fired it up dry really quick and no smoke. Only when water is ran through it. Maybe to much water running through? Any ideas would be great. Or opinion.

Well it dont smell like anything. It has never done that before. I was thinking maybe the distributer made a big difference and its firing hotter? If it is just steam how would you get it to die down.less water pressure?

Yeh they are water cooled. i have a manual valve when it comes off the pump. I havent adjusted that in a while. If thats the deal i should just be able to turn it down some and it should be good. Right?

I think i would wait on a panther guy to comment. 

I wouldn't turn down the manual valve, it could cause engine overheating.  You may have a bad check valve if they are water injected seperately from the engine.

I have had my boat for a couple years. bbc panther logs. put a new carter comp. carb and hei on it. took it out sunday andwhen you get it off idle there is white smoke everywhere at idle is fine. both sides of exhaust. Oil isnt over filled, oil is clean. I fired it up dry really quick and no smoke. Only when water is ran through it. Maybe to much water running through? Any ideas would be great. Or opinion.

Is this the first time you've run it this year? If so, could be as simple as rotten valve stem seals or valve cover gaskets or exhaust manifold gaskets, or a combination of all three. Might have nothing to do with the upgrades.

Ray