chevy 502 exhaust reversion question???
 

looking to buy a motor from a local guy. its a 600 hp 502. I'm concerned about reversion happening but I cant seem to find a good answer on if it will? cam duration @ .050 is 242.6 and 254.6. I have stainless marine manifolds and risers. the risers are about 18" plus long and the water exits the riser towards the back. close to the transom. seems with the way it exits and the angle of the risers where it mounts to the manifold and where it exits the boat it would be hard for the water to travel back up the exhaust. anybody know????https://cimg7.ibsrv.net/gimg/www.off...67493fc433.jpg
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whats Lsa?

Lobe Seperation angle

many things can promote water reversion. Alot of times it can be the waterline height - that height needs to meet a min distance from the bottom portion of the riser. to the waterline. One has to test that end with the boat in the water and how the boat is going to be loaded plus with a FULL tank of gas -- plus all the batteries, stereo equipment and so forth.

Next is idle settings - if too high at shut down - and the engine diesels -- that will cause reversion.

Ign. Timing can play into it as well for idle / rpm speeds / along with misfires if that is taking place as well.

exhaust manifolds and risers too cold -- creates condensation that runs down the internal walls into the exhaust ports.

and of course there is more along with the cam / valve overlap

the lobe separation is 112 or 114. he couldn't remember off hand. didn't have the spec sheet in front of him.

placement of weight especially at rest or idling around

boat traveling in reverse

chopped the throttles quickly .

Seen many at party cove with like 10 people jumping around and hanging out on the swim decks, That is a huge water reverter. Those are the engine that hydro lock at party cove. Always know those and those call ins. .

do you know what the proper height should be? from water to manifold? I have flapper on the outside of the boat. should help with while were floating.