7.4l Convert LH to RH
 

Can someone give me advise on how to convert a LH rotation to RH rotation on a BBC

I just picked up two fresh re-man'd engines but one is LH and I need them both to be RH....or vise versa?

I have someone to do the work, but need the parts. I am pretty sure I will need cam, gears and timing chain.....any thing else?

We can I get this stuff for stock merc marine, does it match up with automotive?

Is there a way to tell what cam is in the RH motor with out removal so that I can math them up?

The RH motor does not use a timing chain. It uses gears to reverse the rotation of the cam. Those parts are available from a Merc dealer.
What is the motor? What HP and what year? Carb or EFI?

It may be easier to reverse rotate the trans.(I assume it has a trans and is not an I/O) Eddie

I don't know exactly which parts you need, but all merc engines are left hand.

Rene

Merc did offer some LH motors in the MIE(inboard) version.

It was a trans set up at one time, but I am running I/O. I bought these as re-man'd long blocks and am not sure what the set up is because the engines are in transit. However I was told one is RH and one is LH. Early 7.4l BBC with reman sheet that states 350 HP from Daddy'os marine??

Not sure what I am getting into, but they were a cheap home for my exhaust, blowers and other parts. Just want to get this thing wet for the year.

It sounds like it was originally a 340 MIE. If that is the case, then it is possible that one of them is a LH. You can easily convert the LH back to RH if you want.

Guys, just to confuse everybody someone decided a long time ago that in the marine world LH = standard automotive rotation, it is determined while looking forward from the rear end of the engine. So a RH engine is actually opposite rotation. And yes the inboard version was sold in both rotations (by Mercury) until the early 90's

Look the parts up for a 340 inboard. You'll need to know year for Mark IV vs Gen V motors. The velvet drives equipped inboards required a reverse rotation motor.
The crank goes in reverse. You'll need a standard rotation rear seal.
The cam spins in the standard rotation direction. It uses two gears, no chain, to accompluish this. So you'll need a timing chain and gear set. Let me know if you want to sell the old parts, I might be interested.
You'll also need a standard rotation cam. The distributor will work, but firing order is changed.
The question I have not been able to get a firm answer to is if the pistons are turned around on a reverse rotation motor.
Anyone know????????????????????????