Cobra 4.3 compatible for 5.0 engine?

[jajin2004]

I have a 1986 rebuilt 4.3 Cobra with a gear ration of 21:19. Can this be used with a OMC 5.0? I know it will bolt on, but should the pitch of the prop be changed, and what pitch do you recommend. Thanks

 

[Don S]

Re: Cobra 4.3 compatible for 5.0 engine?

You need a different gear ratio. You can adjust the prop to get WOT rpm, but you loose effeciency when you get out of the props most effective pitch range.
Cubic Inches of the V8 gives more torque as compared to the V6. Torque is what gets the boat up to speed, HP just keeps it there.

 

[chiefalen]

Re: Cobra 4.3 compatible for 5.0 engine?

1986

4.3 upper 21:19 Lower 14:26 total .60 overall 1.68

5.0 upper 21:17 lower 14:26 total .67 overall 1.50

You decide," ME " you already have it, will work prop your gonna have to play with pitch wise.

 

[Bondo]

Re: Cobra 4.3 compatible for 5.0 engine?

but should the pitch of the prop be changed, and what pitch do you recommend.

Ayuh,...

Going from a V6 ratio to a V8 ratio would be about 2" to 4" of prop pitch....

 

[chiefalen]

Re: Cobra 4.3 compatible for 5.0 engine?

What motor is this 5.0 omc and year? You have it in your hands the motor and drive ready to go? With everything you need??

4.3 motor could give 205 hp, so you wouldn't hurt the drive, at all.

I can't believe this i have to disagree with Bond-O, And Don, and Bubba.

And there is no one i respect and admire here more then these 3 guys.

That motor might not give more than a modern 4.3 i need to know hp and torque.

 

[Don S]

Re: Cobra 4.3 compatible for 5.0 engine?

That motor might not give more than a modern 4.3 i need to know hp and torque.

You do realize that Merc and Volvo STILL have a different gear ratio for 4.3 engine and V8's. Doesn't matter what the HP rating is.

i need to know hp and torque

I don't need to know either, and the torque specs are not known for sure by anybody, let alone 99.9% of the owners.

 

[chiefalen]

Re: Cobra 4.3 compatible for 5.0 engine?

Motor an drive here both OMC, i gave the specs for the drive for the drive and 5.0 motor and 4.3 motor all 86' .