Daddubo
New Member
Your Mercury manual has been superseded. Check the oil FAQ on the Mercury website.
There's no difference in GM engine's camshafts between what GM installed in vehicles and boat builders installed in boat. Oh maybe way back in the 70s and maybe even the 80s there were, but I doubt that there's been any difference between a marine or land-going 350 or 454 in the last 20 plus years. It's been a heck of a long, long time since you could walk into any automobile showroom and purchase a passenger car with a big block V8. 1978, I think. They're all truck engines.
You are correct on the truck engines that is what I meant by automotive. The only difference is when you get in to the Hi Performance engines then you get in to heaver duty parts but those are hand built , the 330hp are just stock non emissions truck 454's I believe the 365hp just has a hotter cam.