I am currently in the process of building a pair of brand new 555's. One for my 28'cat and one for a friend's 29' Warlock V-hull. They will be identical except mine will have a 420 megablower and Stainless marine gen 3 exhaust. His will have an 8-71 and CMI headers.

Merlin 3 blocks
4.560X4.250
Brodix 325 heads
JE -20cc blower pistons
Crane 651 cams
Cometic .040 head gaskets
pistons .010 in the hole
C.R. aprox 8.5 to 1

Just looking for around 800 reliable HP
Both will be dyno'd in full marine trim and I will post the results in a few weeks when they are completed.
Should be a good baseline comparison between blowers and exhaust

Of course, I will have to keep swapping pullies on mine until I make more power than his does

If anyone sees something fundamentally wrong with this combo, feel free to call me out on it before I get too far along.

We already own the blowers and cyl heads, and are being reused from previous builds.

I like the 555cu/in choice ! Thanx for sharing the thread!

I wish your pistons would have worked for me, but I decided to keep it simple and use a 4.25" crank

MT, you want to run that through your program and see what they SHOULD make?

both will make 800+by accident.tuned correctly should be closer to 900 hp.

What rockers are you planning on running

Snap, are they both intercooled? Or neither?

What carbs you guys running?

Here is a link to my 555 build for reference..

I have a set of Harlan Sharpe, 2 set of Crane Gold and a set of Crower stainless. Whichever ones set up the best. all 1.7's

800 Holleys to start out with, because that is what we have. Will see how they do on the dyno and go from there. Being prepped now by Ken Jones performance. He is somewhat of a legend around the Midwest, but mostly in his own mind. I will most likely end up with fuel injection on mine if it turns out that I like this boat.

The 8-71 has a chiller, I would put one on the 420, but where would I find one?