Along with this site I started a journey of my first boat purchase and first engine build for marine use last year and here are some of the mistakes I feel I did. One was choosing the wrong lifters, I know there has been a lot of discussion on here about hydraulic rollers but here is what I found. The Howards 91161 are the lifters I got to replace my Howards 91162 (these are expensive race lifters with .750 wheel) which were very noisy at idle and my cam profile was too small. Funny that Howards said to run 10w/40 for the noise, don't most people run 20w/50 in race/boat motors? I also installed an anti-caviation pump which was also a mistake because we do not run wide open all the time we are usually idling, pulling the kids slow on the tube or just cruising and if we do it is only to 5600 rpm. This is also the third time for me pulling the motor this summer for oil leaks, one was a dipstick tube, Hardin Marine filter relocator (still leaks at filter base), then finally it started blowing out the side of the pan (milodon 12 quart offshore pan). I also installed K&N valve cover breathers that misted everything with oil so I cleaned that up with some 12 an hose and a vent tank. So with some new lifters, a standard melling oil pump and some greater attention to detail I am hoping to go without issue the rest of the season.

Exactly why I'm keeping everything OE except those upgrades that make maintenance easier or longer duration. The only "upgrade" I'd consider that you employed is roller lifters in place of my flat tappet but only when/if I need a rebuild on '96 7.4 Lx MPI's (currently 263 & 80 hrs on them). I like you are not a WOT user as the wife is typically on board and isn't a fan of it, so no point in monster hp engines and the issues they tend to bring.

Lifters can be replaced with engine in place, obviously. What does the anti-cav pump do that makes you decide it has to go now?

Just because like I stated this motor is not a high rpm piece right now. I just saw lower pressure at idle with the 10w/40 that howards suggested still 25-30 which is not bad but since the pan was off thought I would put in a standard pump and see what pressure I see at idle.

Easier for me to pull the engine as my neighbor has a forklift and makes my life easy. Got it down to about 30 minutes to pull including the outdrive.

I believe the anti cav pumps give you low oil pressure at idle?

I'm also having trouble with the Hardin bulkhead leaking. I've tried over tightening, under tightening, different thread sealers, and the "Out" port will not stop leaking.

The 91162 is the "morel" 4603 lifter. The morels certainly arent the quietest lifter , if that is what you are after. I've had em for about 5 years, they make some lifter noise when cold. Nothing horrible. I have found they are quieter with a full turn past 0 lash, than say, 1/2 or 5/8 turn.

The 91161, is, I believe, an imported lifter. Im not 100% on that, but I could have swore they were.

I know a bunch of guys swear up and down the oil grade is responsible for the lifter noise/issues. I personally havent seen any difference whether its 15w50 synthetic, or straight 50 dino oil, or 25w50, 15w40, etc.

I just swapped for the larger filter you can run on that remote filter. It is huge and the gasket goes all the way to the edge, so I am hoping this helps seal the filter. I used lots of teflon tape on my connections and had to do a few twice because they leaked.

You know Teflon is pipe threads only, correct? AN or any other type of flare or compression fitting uses the seat or OD of the tube to seal. And any Teflon on them will cause a leak.

This is for the pipe thread portion in the remote oil filter piece. The AN connections don't leak

That HP4 is huge lol. I'm running the K&N HP5001 as well as it's hard to find a wrench to grab those filters without the nut on the bottom. I also had problems with leaking around the filter lip and just gave it a little extra nudge on tightening it. It's a mother to pull off but better than leaking, although a lot of what I thought was the filter leaking was the fip fitting leaking onto it. The best luck that I've had with the pipe threads was about 4 wraps of the yellow teflon tape and it still weeps after new fittings as well. The flare fittingsvsealed just fine.