454 magnum EFI performance
 

I just acquired a 1995 Baja 32 caliber and it has 2 454 Magnum EFI 385hp engines. I was told the boat does 70 mph at WOT. I was wanting to know what were some of the first things yall would do for a few extra MPH. I would love to see 75 MPH. I am more familiar with carb motors so I don't know what would be different in regards to upgrades. As of right now everything is completely stock. Any first hand experience and recommendations?

I have the same motors in my Donzi. I would pick up a set of K&N flame arrestors Talk to Bblades about some labbed props and enjoy it gets real expensive beyond that.

If you want to spend a few grand more look for a set of Imco or stainless marine exhaust then remap the ecm's before you do the prop work. I have seen 4mph with 502 mags going this route

It all depends on how much you want to spend. 5mph might be pushing it without spending some serious coin.

How many hours are on the motors?
What props are you running now?
Have you yourself verified the boat does an honest GPS 70?

From what I’ve read and witnessed in real life you need about 20hp a side for 1mph on a typical v bottom. So you’re looking at 100hp a side for 5mph.