Swap OMC 5.7 outdrive for no working OCM outdrive behind a 460?

[jesse.burrell]

Can I swap a working 5.7 OMC cobra for a not working Omc cobra behind a 460? Are the gear ratios the same? And if they are not does it matter?
Thanks fir the help...

 

[Bondo]

Ayuh,..... Welcome Aboard,.... I think you'll find they are Very different drives,.... Cobra, 'n King Cobra,....

Nothin' in common,....

 

[jesse.burrell]

Sorry, both drives are cobra's I think

 

[bruceb58]

It's possible for a 460 to be mated with a regular Cobra.

The difference in gearing for the 5.7 and 460 is set in the upper unit. 5.7 uses 21:16 while the 460 uses 21:17 so the question is can you prop differently to make up the difference.

 

[Lou C]

The King that was used on the 460 had the normal Cobra upper gear housing but the lower gear housing was the bigger unit used on the V8 outboards. So keep in mind that the normal Cobra lower used on the V6/V8 small blocks is not as strong. To make it work you will need to go easy on it.

 

[bruceb58]

The King that was used on the 460 had the normal Cobra upper gear housing but the lower gear housing was the bigger unit used on the V8 outboards.

The King that was used on the 460 had a cone clutch so the upper was different. He is saying he does not have a King.

 

[Lou C]

Nope it was the dog clutch normal Cobra upper mated to the V8 outboard larger lower gearcase. Got it all in my 88 factory shop manual.

 

[bruceb58]

I agree, in 88 it wasn't the cone clutch model. Unfortunately, there were a lot of models called King Cobra but most people usually refer to the cone clutch model as the King Cobra.

EDIT: This is actually a good explanation
http://www.allamericandriveservice.com/OMCCobra.html

 

[Lou C]

Yes Baby King Vs Daddy King. I guess OMC didn't think that the normal v8/V8 gearcase would stand up to the torque of the 460 so they used the special V8 outboard gearcase on these...

 

[HT32BSX115]

Yeah. Had one of those in my Liberator! That "King" Kobra in 1987/1988 was different (bigger) than the other drives. The one behind the 460 was indeed a dog-clutch drive and it held 108oz of oil.

The one that went behind the 350 size (and smaller) engines held a LOT less oil.

In reality, you could probably bolt a drive that came from a 350 to the transom mount behind a 460. (although the yoke might be a different length) The pivot housing is not the same nor is the gimbal housing. The inner transom plate is however identical.

The bigger problem is the exhaust manifolds and coupler (for the 460) .......... The manifolds are simply not made anymore. You either need to use new (old-stock) or used. (or after market stainless steel $$$$$) I think Sierra does have a coupler now but it's not cheap.

And yes, a good running 460 would probably, eventually break a smaller drive..............MAN I'm glad that thing is GONE!

Good luck!


Rick

Oh, ratios..........

Are the gear ratios the same? And if they are not does it matter?

They're close enough to not really matter. 1.43:1 vs 1.41:1 essentially the same..........