MPI will be the way to go. Talk to the engine builder about making sure of MPI Computer Programming compatibility. You are after total "Turn Key" operation with the engine swap. Use that term freely when you speak to purveyors of this type thing. The last place you want to find yourself is constantly needing to "Fiddle Around" with your boat instead of enjoying it.

Also...a 502 will be a better choice because of the new technology associated with it. There are still older 2 bolt main, small port head 454's in circulation that may disappoint you in the long run.A Gen VI 454 is a viable option, just make sure it is in fact a GEn VI and get Dyno Sheets to confirm output. Check references.

Damn $6500 sounded really nice. lol We are trying to balance cost vs resale of the boat so this is especially tough. We just don't want to dig ourselves in a whole that we can't get out of when it comes time to sell.

The boat is now running. You take out a live engine and replace it, you are not appreciably increasing resale. This is not a performance boat. Most likeley buyer won't know or care the diff between engines. Either sell it like it is, or upgrade it for yourself. BTW, an early design 2-bolt peanut head 454 will still be WAY ahead of a 383 small block pushing that large resin bucket around...

Yea...that's where my thinking was with my first reply.

Yeah

I heard I can use my current 350 MAG MPI and have it made into the 383 stroker? That would increase performance (although I'm sure not to the level I would like) and be a lot less expensive.

Let me add a few thoughts....

For your size boat I would advocate a big block.

For resale concerns a Merc drop in engine is going to look more favorable than some modified motor to the average consumer. Get a turnkey 502 and plug it in. Fitting was addressed in other posts.

I would make sure you have an EFI motor.

The increase weight due to a big block is insignificant in the overall performance. It might weigh 180 ish pounds more. That's like one person or half a tank of fuel. That should be the least of your concerns unless you were installing the motor in a 15 foot aluminum Jon boat.

Best of luck

Looks like I'm going to try and hunt down a 502 take out with low hrs this weekend.

I was told my current gauges would not work with a 502?

That may or may not be ...depending on programming. I would suspect that if you get a Merc MPI your gauges would be compatible. Some guys on this forum can chime in but seems to me that a certified Mercruiser guy can tell you what you need to do. You're not the first one to do this and you won't be thew last LOL !!

10 pin or 14 pin standard canon plug would likely determine if the gauges would work. Match the plug and it should work out. The gauges are nothing crazy.