i have a 89 formula that has been upgraded from 454mag to a 502. it does not run a engine oil cooler but does have a power steering cooler. how important is it to run a oil cooler and where can i get a kit with all plumbing ?

Its very important to run an oil cooler. You can buy oil coolers at EMI, CPPerformance or a dozen+ other places. Plumbing will most likely have to be custom depending on where you mount it.

I'm surprised there was no oil cooler on the 454MAG. Is the 502 a Merc motor? If so, again I am surprised there is no oil cooler.

I am thinking whoever did the swap stole the cooler. it also does not have a remote oil filter anymore.. where do the cooler lines go into the block? i noticed 2 plugged holes next to the oil filter when engine was out

I assure you there was one originally....somebody hacked the swap...used a genIV block originally, maybe a V or VI now and the adapter would not fit so they just stuck a filter on it and said screw it !!!! bad move, need a block adapter(where filter is now) good cooler(eddie marine has a nice one) #10 line and ends(twist lock are great easy to do) and a remote filter mount( moroso is great) had to do my last 2 boats, the first for the same reason you are now...

fireboatpilot got a couple for sale at this link:http://www.offshoreonly.com/forums/s...l-coolers.html

They don't. Those plugs are for car apps. There should be an adapter on the block where the oil filter would mount that the oil lines go to. Thats standard Mercruiser. If its missing, CP or multiple other places have them.