Performance mods for mercury 250 efi

[rico64]

I am in the process of getting a 98' mercury 250 efi. I want this motor to make atleast 300hp to push my 21 starflite. I'm looking at the mad efi bolt on intake but i cant find no performance gains anywhere. does anyone know how much hp i can expect from the Mad EFI bolt on intake ? Also what other mods can i make to achieve 300hp bench mark without cutting my heads.(dont want to have to run 93 octane)

[vnemous]

you cant simply put you can get close around 285 but thats all without more compression and internal massaging. JMO

[JohnR]

ProMax 300 ignition box will help some, 250xB fuel box will too. The 300 ignition box, a swap to a Merc 4 butterfly intake, and a set of CCM reeds picked me up about 4 mph on my Starliner. Its a little under propped now so there's still more in it.

[vnemous]

The 250efi will already have a 4 hole. You could always put a 300xs crank in it and stroke it, right Chaz