I've got a mid 90's Formula 382 with carbed 502s standard 415hp. At a point where I have to either rebuild or replace one. I have seen several Crate engines around the web but after reading posts on OSO not sure about reliability of GM's contractors assembling them. Good or bad would like to get some input.

Mercruiser black motors are all gm marine series engines. So they would of come assembled by gm. Just make sure it is thier marine motor and you should be ok as long as you understand it is a stock replacement and not a hp unit.

If you are not looking to upgrade power, there is nothing wrong with GM crate power.

Yep, and the latest Gen VI 502's have been dyno'ing between 445-465hp depending on induction and exhaust. That's on 87 octane. Nothin wrong with that.

If they are Merc 502's then they are 390hp. IMO, its probably more cost effective to rebuild what you have.

Thought about boring the old block to 540 to bring it up around 550hp. Which brings up another question. If i did only one side this season am I going to see a lot of issues with 550hp on one side of the boat and 100 horses less on the other?

I would go this route as well, not even to 540, make them 509's with stout parts and you'll be miles ahead. might even be able to reuse your crank. with the right cam/head combo you could easily have more hp and great reliabilty.

the new crate engines you see listed all over are NOT assembled by GM, they have a outsourced place doing the assembly...and the quality is shaky, bought 2 had a bad experiance with one and after doing research some others have as well...have a good machine/engine shop redo what you have...

+ 2. 509's. Your drives will hate you going to 540's.

Is that power meassured by the SAE J1349 Standard that Merc, Volvo and Ilmor uses or the genrous SAE J607 Standard many custom builders use? If the latter they would be between 425-440 hp SAE J1349. The reason why I'm bringing it up, is just to make the hp comparisons equal.