Marinizing a 454 short block...
 

Hello all,

I have a 454 Gen 5 in my jet boat that has a cracked block. Casting number on my cracked block is 10114182. I took my rectangle port heads to the machine shop to check for cracks and they said it's still good.

I found a company selling a used truck 454 short block with the same exact casting numbers (10114182) on it. What exactly do I have to do to marinize this truck block? Or should I tear down the truck block and put all of the stuff on my cracked block onto it? It just looks like a huge job tearing down the block...

Also, once I remove the bolts on the engine mount, how hard is it to remove the engine from the jet? Or should I remove my jet pump first, then remove the engine out of the boat?

I'll attach some pictures to give you guys an idea of what I'm tackling here on my next post since I can't find that attach button on this post for some reason. Any help is greatly appreciated.

John

Okay, for some reason I can't figure out how to attach the photos. Oh well...

No need to bolt the jet off.

The engine comes off by itself and all you need to do to the block is to use Brass freeze plugs and a marine gasket set, plus bolt all the former accessories and stuff from the old engine on it.

So just buy some new brass freeze plugs and marine gaskets and that's it? Wow! A lot easier than I thought. I just hope the short block I'm buying is in good condition because I'm getting it shipped to me. I can't wait to put this boat back on the water. Thanks Mikey!

What about the Water Jacket Drains on each side of the marine block? Does the truck block have them? Pretty important come winterization time.

I'll have to check with the company selling the block to see if their block has the water jacket drains. Will call them tomorrow morning.

same cam?

Engine internals might all be different. Comp. ratio, cast or forged crank? The cam is different for sure. I'd say tear the cracked engine down and install the parts in the good block. Have the block cleaned and a fresh hone, new sets of rings and bearings and marine gaskets. Have the machine shop do the brass freeze plung honing and cam bearings and then you know exactly what you have, fresh! IMO

That's what I was afraid of. I'm doing this myself and scared to tear down the block. There's just so many parts to tear down that I'm scared there's gonna be some extra bolts left. Does anyone know if anyone did this and posted it as a "how to" section on this forum or other forum?

X2...Defintly. It may take a little more time and money, but you'll be knots ahead!