And like a 420 too sans the intakes.
Whats the carb in it. I figure it has Weiand TeamG intakes with a Holley Dominator 4500 flange so that would tell NOT being 420´s or the intakes have been changed from stock 420´s as they had two planes.

Also the block is a Bowtie instead of a GM production one as it´s not possible to build a 540 out of a stock block.. not even a tall deck.
It´s been a few years I dug into a boat with triple 575´s (Cougar 46).

It´s Holley 1050´s on them. And its bowtie block, and the 575´s was built of bowtie blocks.