Cam duration and water REVERSION

[Moneypitt]

So, now you're asking about headers? That is a whole different situation. The "log manifold" part got you alot of useless information about water reversion. Now you have to get serious about cam choice if you plan on running water thru the headers. The area of overlap is where you must be careful. You also must devert some of the water flow away from the headers with additional "dumps" overboard. I also restricted the flow to the headers with "pills" in the fittings. Each set up is a little different. I have been told the "t" ball check valve is to be closed at idle and only allow water to flow a "givin" RPM, (water pressure), from the jet.........Good luck.........MP

[SmokinLowriderSS]

Over transom or thru-transom?
Injected headers or jacketed headers?
The injected will likely run you the greatest risks of reversion problems, and like MP said, everyone I have seen discussed had them dry at idle to a bit above. I suppose there is some risk of reversion with jacketed headers if the collector dumps aren't far enough back (or "downhill" on thru-transom ones) but it is less of a risk. My duration should be no problem for my jacketeds. My hydraulic cam is only running 280* seat/seat with .572" lift.

[WHATA SQUIRT]

smokin' the headers will be a through transom.water jacketed,most likely a lighting-most reasonably priced.

[Marty Gras]

If you are worried about reversion, have your exhaust valve close at ZERO! The longer the exhaust valve is open after zero, the more you have a 'reversion' problem. The problem between 'max power cams', and the cams that really work in a marine motor, are the 'reversion problems' and how to control them. You can advance a 'performance cam' to get the correct exhaust timing, or just have a cam made for your use.

[HotDogz]

Take a look at Paul Bassetts Tri-Y TT, SS water-jacketed headers. Replaced my logs with em because of reversion but picked up 300 rpm just puttin em on. With 244* @ .050, I was pulling water back into the logs, wouldnt idle.
Bassett Racing (http://www.bassettracing.com/newpage11.htm)

[SmokinLowriderSS]

I've seen a set of Bassett Tri-Y's @ HTP's shop, and drooled suficiently (not on the chrome tho). Well outta my price range at this time. I found a set of used Lightnings that still set me back $1,500 by the time I bought 4" outlets too (oh yea, that damned 6.9% sales tax).