Where can I get a 140*T thermostat for a Merc 496?

Why 140* and not the factory 160*??

Cooler air more power.

140 is the stock t-stat for many mercruiser motors with fresh water cooling. West marine (Sierra Brand) should have them as will most marine type stores. Don't use the automotive type.

Here is cp's one http://www.cpperformance.com/detail.aspx?ID=695 dont know if it is the right size for a 496, but I assume that it is.

Boaters world http://www.boatersworld.com/product/356330951.htm

If the factory designs them (496's w/ closed loop cooling) to have the 160* thermostat,, wouldn't running the pistons cooler impact the the fuel/air combustion properties? maybe causing carbon buildup on valves etc due to lack of a clean burn?...assuming nothing else has been modified.

140* water temp won't make the intake air any cooler. Its set up to maintain constant temps with a 160* and the best performance.

Thanks!