If there's a bypass oil filter installed, plumb up an adapter that's in the flow from the block to the filter, as close to the block as possible. The oil moving from the engine to the filter will be within a few degrees of the temperature of the oil in the sump, and it won't involve making any permanent alterations to the pan.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!