View Full Version : LH vs. RH

01-04-2011, 11:56 AM
Guys i need a little knowledge. If i change the engine from a ford to chevy i know that the rotation changes most likely. When that change occurs does the trans change and if so what changes would that be. It is a velvet drive. I'm asking for a friend that has an old mustang like my s&s. thanks for all the help in advance.

01-04-2011, 12:31 PM
ford spins opposite of chevrolet:confused:

I did not know this!

I know marine engines can be right or left rotation, like larger vessels with 2 rear engines
clockwise and counter-clockwise

but, aren't we talking about automobile engines that have been marinized? in a sense of the word

01-04-2011, 02:09 PM
Will post up a pick if I can find it...
Short story is the pump housing on the tranny will need to be rotated. Not sure about the adapter housing.

east tx skier
01-04-2011, 02:32 PM
If your Ford is left hand rotation, which I thought all MC boats were, the Chevy you replace it with will also be left hand rotation. I know some earlier Correct Crafts V8s had right hand rotation engines, but even they switched over to left hand rotation engines long ago and accomplish the right hand rotation of the prop with the 1.23:1 gear reduction transmission.

From another forum:

"On PCM Engines...the Serial # plate indicates both engine and propeller shaft rotation. (Example: PLD-WV-R20 and PLDWV-L20). The "L" following the "P" indicates the engine rotation. The "R" and "L" following the "V" and preceding the "20" indicates the Propeller Shaft rotation."

From further reading, it looks as if most of the marine industry went left hand engine rotation in the late 70s save for Correct Craft, which didn't switch over en masse until it started using the transmission to change the rotation. So if your engine is RH rotation, you may want to do some research concerning whether the hull had any design components in it to compliment that rotation. If it did not, then, swapping over to a LH rotation engine should present no problem other than the fact that it is a smaller hull and you will be shifting the torque from the rotation in the opposite direction, which might cause the boat to ride a bit differently. Of course, if the hull was designed to compliment RH prop rotation, then my bet would be that you need to figure out what to do to make that Chevy turn a RH prop.

/Edit: Didn't see that this was not for your 84, but rather a CC mustang. Yes, that boat will have RH rotation from the engine. Go do a search on "reverse rotation" on Correctcraftfan.com. There's a lot of information on this over there and a lot of guys with that vintage of boat. You also might tell your friend to get in touch with Jody at Florida Inboards (http://www.floridainboards.com/). He can probably tell you whether the Mustang hull was designed for RH prop rotation or, if not, he may have some parts to make a LH Chevy turn right.

01-04-2011, 05:37 PM
thank you guys a bunch!