For engines of that displacement, do not be alarmed if you see temps from 250-270 degrees F. That is actually normal. Now, if you see 300degreesF, richen it, you probably are running too lean. If tuning does not correct 300degreeF, try changing you plug to a more suitable one. If that does not work, take off the head and make sure you have the proper number of shims for the correct compression ratio.

Also, make it a practice to RTV seal your engines to eliminate possible air leaks. 9 ntimes out of 10, air leaks dont happen, but taking this precaution can save you alot of headaches.