Not trying to sway you on the cooler I know the ilmore has a fuel cooler but they also have the pump getting cooled by the fuel. Merc 1075 has Weldon 2025 pump and no cooler motor on that pump is not cooled by fuel.

You mean the fuel pump heating the fuel. not the other way around. lol
Not talking about the Weldon.

The 20* stuff has the same or less CSA than the large conventional heads (380-400cc). The runner is longer, not a good metric. I think youd need a 632 at least and 665 would be just right for them.

There's some discussion on the ports and CSA if you dig on chevelles or yellowbullet. Saw it the other day.

Any thought on lifter and spring oilers ?

Just curious. Did you get the heads raw? No seats or guides...

You are forgetting that this has to make power from 3000-6000 rpm. A 665 at 6000 rpm moves around the same amount of air as a 540 would at 7400 rpm. IMHO most of the marine builds use heads that are sized more for drag racing than endurance. You have to forget about trying to make more peak power in the last 500 rpm of the curve and concentrate on making a bigger curve. ;)

No. they were ordered bare cnc with seats and guides.

I have valve covers coming from Billet Fabrications with spring oilers integrated in the covers. I'm also doing piston oilers of which I will post photos of the installation/modification procedure. I'm not doing anything special for lifter oiling.

Piston and spring oilers will be installed 4 sure on those. ^^^^ jeez you beat me to it ^^^^^

I thought you were working - you know on a 665 CID for some kind of boat ^^^^

Had to mess with you early here

BUP and I have discussed this as I wasn't too concerned with the fuel cooler using a full return open loop fuel system but apparently there are a lot of boats that suffer from vapor lock or fuel boiling. In the end I don't see where a fuel cooler does any harm other than adding a little weight and complexity. Personally I like to keep it simple but I don't see any harm in a fuel cooler.