I had windage/aeration and oil pressure issues, went to a wet external oil pump and welded in a full windage tray down the entire oil pan and all that went away.
I have no room for a full dry sump system plus the cost is much more.
External oil screen and pressure adjustability has come in handy and saved me from having to pull engines and pressure is always good.

https://cimg6.ibsrv.net/gimg/www.off...c0ce3ffe01.jpg

More pics as requested (Stewart)

-16 bung welded to bottom of oil pan. and full windage in the oil pan .
I wanted to prevent the swirl affect at the bottom of the oil pan so I welded in a "diffuser"

https://cimg8.ibsrv.net/gimg/www.off...93de6bacd9.jpg
https://cimg0.ibsrv.net/gimg/www.off...a11f421834.jpg
https://cimg2.ibsrv.net/gimg/www.off...96db9f81ec.jpg
https://cimg8.ibsrv.net/gimg/www.off...75825517f6.jpg

Thanks Dan! lots of help as always!

I'm running a GZ 102 pump on my 394 sbc marine build. Mahle power-pak pistons with 1mm, 1mm, 2mm ring package. running 6" of vac. while in boat. engine dynoed at 530hp / 519 tq. with dyno headers. 12" vacuum on dyno was 21 hp better than no vac. Most of the gain was from 0 to 6". I'm an alpha drive setup so no sea-strainer / water pump, just the GM style circulation pump, but I made wholesale changes in accessory drives when I changed over to a vac. pump. I went with a type 2 power steering pump, reduced my water pump and alternator rpms, and used a crank mandrel drive to run the vac. pump. I sent the pump in after 1 full season of boating and it was still good, no need for new wipers.

https://cimg4.ibsrv.net/gimg/www.off...ea7be71fab.jpg

I ran an Aerospace Components vac pump on a 632 years ago.
Couldn't say whether it made me HP or not... but I can say the engine never leaked a drop of oil anywhere. lol

Yep, pretty much agrees with what I seen and have tested, talked to other engine guys who've tested them on their dynos with/without.
on a recent 565 I dynoed that had a kevko full box wet sump drag pan with every kind of windage control, kickout, baffle etc I saw a 18 hp increase without/with then without at the 860 to 880 hp area on my dyno for peak. They were standard tension rings, motor had less then 5% leakdown and no visible blowby or vapor even at wot from valve covers.
The next gain which Id be NERVOUS about doing on a 100 hr rebuild interval endurance engine would be to use a thinner, more delicate low tension ring package which is proven to increase hp at expense of long term ring seal then "help" the ring seal with the vacuum pump. Would be fine on a 10 hr rebuild interval engine but Im not rich like my friend ICDEDPPL who doesn't mind rebuilding his engines every season (joking).
Yes, ideally a dry sump would trump all this but most my customers and myself don't have dry sump "money", Smitty

How many hrs on your setup so far, did you do anything extraordinary like piston oilers and what vacuum are you regulating your crankcase at?

Had a short season this year with work schedule. only 46.2 " in boat" hours since vac pump was installed (not including dyno time). Engine had 51.3 hours on it since build before the vac pump was installed. I build the engine with the plans for a pump given the piston / ring package I went with, but didn't have time to tackle the accessory drive issues before the itch to hit the water came in 2021, thus running the engine some before the pump install.

I have vacuum regulated at 6" Hg. I plumbed an additional gauge in the dash so I could observe if I were to loose vacuum or have a regulator issue and create too much and cause pin oiling problems. I tried a couple different pulley configs. and ended up spinning it with a 3" crank pulley and a 4.5" pump pulley. The pump is turning about 2550 rpm (1700 engine) when the vacuum reaches the 6" regulator set point. Obviously every engine combo will be different and will change as rings wear.