I have a 454 and after running it awhile the oil gets hot 230+ but only if you take it over 3500 RPM. The water however is fine, what could be the problem?

Could be a blocked or too small cooler, my 502s did this and with new larger coolers it stopped. If you lost an impeller in the raw water pump it can block them, you can try to back flush it to see. Also what oil are you using, some are just not thick enough, like a 30 weight, I used 50 and it helped. Could be a T stat, some have them on the oil coolers too. It is a chase, you need to start cheap and easy and move to hard and expensive...like new coolers.

Thanks Mitch, I thought it might be the oil cooler since it seems to be the size of can of red bull. Alredy have a new one from my last boat that never made it on. Hope it solves the problem.

You may be surprised when you take it off, it may be all clogged up too. If you just have one it is no big deal, I had 2 and it was a bear. Make sure it has a P Stearing cooler end to it also.