My 223LS formula has the 454 mag with an alpha outdrive, yes I know that drive unit really doesnt get along with big blocks but heres my question-I changed the oil about 20 hrs ago and I'm changing it again, what oil would you use in an alpha to extend its life??? I'm thinking Royal Purple Max-Gear?
75-90? I baby this boat on take off and am very careful when it comes out of the water so I dont blow this thing up but I want to give it the most protection I can. Presently I switched to RP 20-50 Synthetic for the motor with no problems. Thanks for all the help I've recieved on this site its a great place for info and making friends.

The RP would be a fine choice.

I've used the Merc Hi Perf Syn from 92-2002. Since then i've been using Mobil 1 Syn 75W-90. All are 25-30hr change intervals. I also run a drive shower and gear lube resevior to keep things cool and lubricated. No blown Alpha's over 4 350-400hp SBC's.

Well old oil had about 20 hrs on it and was pretty darn clean when it came out, had to look real close to see a few small micro hairs of metal on plug magnet. Filled with royal purple 75-90 Maxi-Gear so lets see how it does. Thanks for the info guys.

put a Simrek drive shower on it for sure.......