what do you have for intake and carb on the mk 4? the efi is a nice setup, but rarely trouble and bug free. I would consider the efi conversion for over the winter. where do you run this boat? I was assuming mag carb engine.

I run in the upper Chesapeake around Elton Maryland. It has a dual plane edelbrock air gap manifold and a 750 edelbrock carb

Good carb and manifold. Does the trick. If you tried that efi with all its foibles, you would be chasing bugs all fall. Like the VST setup. Cantankerous. The injectors themselves need cleaned and flowed, or better yet replaced. You spun bearings in the mk4. Your bottom end work? Or having motor built?

I might pull the bottom end of the mk4 just to look myself but it's been built about 5 times by 2 different builders and every time after running at 5k rpms for 5 minutes it blows the dipstick and wipes the bearings

When I take the mag motor apart I'll check the bearings as you suggested

That mk4 block is ready for its next career as a mooring anchor in Georgetown yacht basin...

hahaha. That it is

My friend has a 454 marine short block for sale 631 902 4665