Shah Mat

I have read most of the threads regarding reversion and learned a lot from them. I'm kinda new to this because I only know drag race motors with HUGE rollers in them with no water worries.

Is some reversion ok? I do occasionally go through long no-wake zones sometimes with 35 minute idle times.

Is one brand of headers/manifolds better than the others to prevent reversion? Can I go with high performance manifolds with long risers, or should I stick with tubular headers? I was looking at Lightning headers and I definitely want to keep the exhaust wet. I also see used CMI's on here and E-bay all the time. I have been told that dry exhaust is much louder which I do not want. Motor is a 540hp 502 with a slightly larger cam than a hp500. I will post cam specs later today.

The motor was a big purchase and the exhaust will be too. I want to get the right set up the first time around.

Thanks

TomR

Reversion is not good!! Depending on how bad, it can cause everything from corrosion to crystalizing valves. Both of these things can cause catastophic failure!!
You are more likely to have reversion with real tube headers than manifolds.
BUT......if you want to maximize power, go with the Lightnings Headers. A motor that is properly tuned will see at least a 20hp advantage over "performance" manifolds!
Unfortunetly you will at minimum have to run reduced water and quite frankly I would go with dry. You could get tailpipes that mix the water just before the end of the pipe. I have a combination of overboard dumps and the mixing of water in the end of the tailpipe.
If you are afraid of it being a little too loud, add a set of Shotgun Mufflers by Drew Marine. Again, this is what I have and it has worked out well!

Gary C

I recommend getting the Stainless Marine manifolds and the long risers. I just put them on my boat. I went with the long risers so I can upgrade my cam later. Call Brownie he can give you the scoop for your motor.

Shah Mat

Is this too much for wet Lightnings?


Duration @ .050 236/242

Lift .589/.612

LS 112.0

Linster

I know CMI elbow tops can handle that cam. It will only make a little power difference as said above but will sound a whole lot better .

Shah Mat

What are the differences in CMI's? Elbow tops and what other kind is there? Anyone have pics to show me? Do they require tailpipes?

TomR

I would definetly be concerned about reversion with that cam! You need to introduce the water into the exhaust as far out as possible. As I stated earlier, headers will increase the reversion.

Cord

iTrader: (2)

Because you are N/A you need as much primary length as possible. As fine of a header as they are, CMI elbow tops are too short for you. Needing a long primary, your choices are pretty limited. Most people will just step up to a full tube header or the Lightnings. SOME manifolds have a tail that will convert them into a tri-Y setup. That is acceptable. The other choice is to use some Eickert manifolds. The Eickerts may be the perfect header for your application. Nice and long primaries. Plus, there is a set for sale in the parts section. The used Eickerts are about the same price for new a set of Lightings. Plus they won't rot out or crack and have a longer primary than the Lightings. Be sure to measure your existing cut out to see if they will work.
http://server2.offshoreonly.com/foru...threadid=73361

Shah Mat

Thanks

So the longer the primary tube, the more resistant to reversion?

If I buy a set if Eickerts or Lightnings and try them, is there a way to check for signs of reversion, and if so, go with a smaller HP500 cam?

Cord

iTrader: (2)

The primary length is meant to help your engine build it's peak torque lower. The length doesn't affect reversion. It's the point that the water is introduced. That's why many people use a dry or reduced water tail. The fall of the pipe also plays a roll in reversion. So does idle speed. When my motor starts to revert, I can hear the change in tone. The engine will revert the worst at idle. Let the engine idle for a long time with the water on full. Try to match your running water pressure. Shut the engine down and pull the header. Look in the header and exhaust port for discoloration or water. Look at the valve and plug. A valve or plug that is getting wet will be spotless (clean).