As said, water temp won't be the problem. Oil temp will. Personally, I wouldn't do it on a street application. If you decide to do it, I wouldn't go over a half fill - and count on using an oil cooler. On the plus side, todays lubes ( especially synthetics ) can handle ( and are designed to run at ) much higher temps than in the past. Running oil temps in the 250 range are not uncommon.