I have 502 Dart Block Supercharged Engines with 250 B&M Blowers with 7 lbs of boost. 605hp at 5500rpm. At startup, my starboard engine blows out a cloud of white smoke. When cruising, I can see a little white smoke, but not much. This started happening after I ran my engines hard for about 10 seconds and got my oil temp to 255-260 degrees. What are the possible things that could be wrong?

First thing that comes to mind is a blown head gasket. Did the engine water temp go up as well? Any signs of water in the oil?

I would also check the exhaust risers for the possibility of water leakage back into the engine.

BTW, if it only took 10 seconds to raise your oil temp to 260*, you have an engine oil temp issue. You may need to add alarger oil cooler, especially with the supercharger. What did the oil pressure go down to when this happened?

valve seals?

I know I need larger oil coolers. After about 10 miles of cruising at 3000rpm, my oil temp goes to about 230 degrees. I usually set her down and let her cool off before going on plane. My water temp stays the same, around 105 degrees. I have not noticed any water in the oil yet, but that could change over time. Did not notice oil pressure drop, but they don't work well either, wrong sender units I think. How do you check your riser?