just got a new boat it has 2 inboards and 2 alpha 1 outdrives and looking at ls swapping it looking for any info on how to do it

you can look here: starts about the 3min mark

Needs a turbo. I’ve been wondering about an LS swap, a 6.0 with a cam should put a beat down on an 454.

The LS is a great engine, but it needs a transmission with at least 1,8:1, preferably 2:1.
Our LS376/480 was lousy with the 1,56:1 transmission as the propeller spins to almost 4,000 rpm and lacks torque, but with the 2:1 transmission it's a completely different story. I wouldn't put it in the boat without at least a 1.8:1 gear option.

I take you have the motor in a inboard ski boat?

No, it is installed in a 4,900 lbs speedboat with MSA surface drive. With the ZF63A-1.56, the engine struggled to turn the SL5-22" propeller and would not go over 62 mph-Livorsi GPS. After swapping out the ZF63A-1.56 for the ZF63A-2.04, the engine spins Maximus 30" easily and we've gotten to 65 mph so far. It would go far over, but to small skeg made dangerous ride. We are prolonged skeg and on the spring will go back on the water. My expectations are betwen 67 and 70 mph, hopefully close to the 70 mph.

With transmision 1.56:

I have swapped a forged 370ci in a 94 baja outlaw. Message me if you have any questions.

A prop change can solve that pretty quick, but I realize that surface props are not the cheapest to source.

My Arnesons are 1.32, with cupped 25 pitch 5 blades. I don't think I would even try to turn them with SBCs or LSs. It does keep the cruise rpm down though...

Nice clean setup.

Care to share some horsepower and speed information?