How hard to "unreverse" a 502 motor?
 

I have a pair of 502s 415 hp roller cam Gen5 carbed motors in my boat. I am about to rebuild them and one is a counter-rotation motor. I would prefer to have two regular rotation motors since I am upgrading my gears/trans to be able to do the rotation change.

How hard is it to turn my Cr motor into a Reg rotation?

Distributor change.....what else?

thanks!

I'm probably leaving out a few things but..... New timing gear set, std. rotation distributor gear, standard rotation starter.

the cams are usually the same but spin backwards via a gear drive instead of a timing chain.

If it uses a gear drive, then the cam and distributor spin in the standard left hand direction. The only thing that spins backwards is the crank. You will need a timing set and a starter. The cam and distributor are the same as the left hand engine.
On the other hand, some reverse rotation engines turn everything backwards, or right hand. It all depends on which one you have.
Eddie

Don't forget to change the front and rear crank seals to std rotation type also.

Who's doing your engine work?

the destrib is spinning backwards so everything must be spinning backwards on mine. The reason I know this is beacuse my builder (who sucked - Bill's Marine Ft Lauderdale) went through three distributors before I found one designed for a reverse rotation engine. The ditributors kept getting pulled down into the engine and breaking up. The one I found had a bearing to handle the downforce.

I have not decided who to use yet...if I could find a good trustworthy and honest machine shop in the pompano/lauderdale area I would probably get the machining done and do the rebuilds myself (with a buddy of mine who has done some boat big blocks before)......then I would hire someone like Mesa to dial it all in on dyno for me (since beyond my skills). Trying to do it on a budget and learn more about my engines in the process (don't flame me guys - I dont have a mechanic uncle who can teach me the ropes).

The thrust on the distributor might be down, but they all spin the same way - the oil pump only works in the standard direction.