Mercury's new 409 MPI claims to have a flat plane crank, I'm curious what advantage that gives to a boat. I also see in the pictures what looks like a Holley EFI throttle body...?
I wonder if this means Holley will be able to interact with smartcraft/vessel view stuff.
Wonder if anyone knows more about it?

You might be able to spin it faster. What are the specs for operating max rpm range? I'm not convinced this is a replacement for a big block.

Pretty sure this is their 383 with some more cubes and a new crank.

Industry-Exclusive Flat-Plane Crankshaft

what! Need some more specs if anyone knows

O advantage in this application. Sub 6000 rpm small block chevy. Different noise is all.
Look up / google search flat plane crankshaft v8 advantages.

I rather wish they’d spend 5 $ and a few minutes times to make their sbc exhaust manifold water passages line up to their risers.
:rolleyes

Mercruiser. Yup, beware. Manufacturing issues.

Performance 400 horsepower 5000-5800 RPM Exotic idle quality Great acceleration Flat-plane crankshaft 150# lighter than 8.1L Speed gains with Bravo One X

Technology ECM 555 SmartCraft 10-pin harness Engine Guardian MPI fuel injection Mechanical throttle & shift

Black-X valves Dry joint iron exhaust Heavy-Duty iron block Forged crank, pistons & rods Shaft-mounted roller valvetrain Full System Fresh Water Cooling Heavy-Duty Eng. oil & PS fluid coolers

Single-point water drain 3-year limited warranty 25W-50 engine oil Long-life coolant Remote oil filter 87 octane fuel

985 pounds. List price $33,425, available next month.

All that For a 400hp 383 ? Nutz !
Damn.
IMHO as always.

Need to get rid of that single point drain system

Another thought; how are they building a motor without CAT's these days? Would be great if they could, but don't see how.

Maybe this is technically a remanufactured engine and not subject to catalyst requirements?

I also noticed that the Quicksilver 8.1 and the 540 Mag stroker are no longer available. Looks like this is your Mercury sourced replacement for big blocks with a warranty.