Is this a 454 7.4L?

I may have to replace this engine since it may have a cracked block and was told by the techs at the boat shop that if I need to repower my boat, the replacement block has to be the same size big block 7.4L. When I bought the bought 6 years ago I was told this was a Mercruiser 454. Not sure if it was a rebuild or just pulled out of one boat and put into mine. Or if it sat for a while or even how old it is. I do know for a fact that it was installed into this boat in 2015. I don't have the engine knowledge and expertise and, I'm trying to maintain trust in my long time boat shop. Hoping someone here has that skill to look at it and say that it is a 454 7.4L. This may help me with a rough idea of how much a replacement block is going to cost me. Thanks!  

There’s a spot on the Holley carb they missed…that’s a lot of paint.

It certainly looks like a 454, which is also known as the 7.4L, two names = same engine.  The same size engine with identical outside size could be a 396, 402, 427 or 454, heck some were stroked to be a 496.  No way to tell from the outside what it actually is but as noted 454 is the most common.  If it is just cracked from a freeze you might be able to salvage nearly all the internal parts and use them for your new replacement engine.