Should I use a Merc 377 MPI system?
 

I was offered a stupid good deal ("$500, you can have it, because I'm never going to use it") on a very low hours, complete Merc 377 MPI setup (intake, injectors, fuel pump, dizzy, harness, computer, etc.). I've not looked at the parts and do need to verify that it didn't come off of a cat engine.

Building a ZZ4 bottom end with 906 heads, roller cam, stock bore/stroke (4.0 x 3.48).

Stick with a carb and Al dual plane that I already have, or buy the Merc system? Biggest concern is the inability to tune it myself. Need to figure out if the box can be replaced with a Holley or other aftermarket unit if/when the ECU dies.