Replacing 351 windsor with OMC 5.0

[HamiltonJet73]

Hi All

I'm trying to help a mate whose Supra Ski boats 351 Windsor has died. He has been told by his mechanic that the whole motor needs a rebuild so we are looking at the options available.

One option that is available is to purchase a OMC 5.0 ford V8. I understand that this is the Windsor 302 so should just bolt in as a replacement to the present motor, which would make life easy.

The OMC motor is an EFI motor, what would we need to do to get this running? Do these motors come with the electronics as part of the motor or will we have to purchase a controller unit?

If we have to purchase a controler, we might look at fitting the inlet manafold and Holley of the 351 onto the 302, would these fit straight on? what else would we have to change?

Thanks
Adrian

[Jango]

I believe ALL the electronics come with the Motor. You would be much better off using the F.I. rather than a carburator. More power and better fuel economy. The 351 manifold will NOT work on a 302, too wide. All things including mounts should hook-up without alterations, except perhaps exhaust since the 302 is an 1"-1 1/2" narrower and not as tall. 351 Block is wider and taller.

[HamiltonJet73]

The OMC Cobra is looking like the go. Does anyone have any idea how to hook up the Gauages (rev, oil, etc) to the motor? Will it be simply hooking them up as they were or will we have to purchase OMC gauages that plug into the wiring loom?

[Luchog]

why do you want to loose 60-80hp??

[HamiltonJet73]

Do you mean lossing hp in converting from the EFI to Carb or going from 351 to 302?

[Luchog]

from the 351 to the 302. Carb or Efi is not that much of a difference once you got at least 280hp.

[Jango]

HP difference between an older 351 and an EFI 302 should be minimal. However cubic inches mostly determines Torque which could be significant. It may be necessary to change gear ratio or at least decrease prop pitch to obtain "out of the hole power" with some decrease in top end speed.