G’day Guys,
Im in Australia. I have an old 70’s clinker with a Holden 308 ci V8 (Aussie GM) that’s going to be stroked to 355. Head work etc.
I’m new to boats. So I have had a cam ground. 224/234 @ 50 and 109 LSA. This before I learnt about water reversion issues.
I’m getting rid of the water cooled log manifolds and replacing them with block hugger headers reversed so the point up. They have been cut back to where I could fit 3” flanges. From here they connect to 3” exhaust bends the turn down to meet up with the 2.5” copper exiting through the transom.
I’m working on a water injection into each header tube from a 12V pump seperate from the main engine driven pump for engine cooling which will dump in just before the copper tubing. The pump will switch off at idle or there abouts using a vacuum switch
If the water I inject at the headers as a spray/mist be of concern with reversion? Will I get reversion with a LSA of 109*?
Thanks for your assistance Guys.
Al.

Reversion is largely from the injected water getting aerosol'd in the exh, and getting pulled back up the piping to a point where it falls into the exh manifold drop. Water dams at the bottom of the exh man elbows really help at arresting the more liquid flow.

When you run the ragged edge of physics, Mr. Murphy is typically riding shotgun.

Thanks mate, I’m aware of all this hence why I would run a separate pump turned on/off by a vacuum pump.
Cheers.

Depending on what boat you're putting this in,we've had good results with running the Nicson amd Glenwood style aluminum log manifolds upside down. So the exh man ports from the turn down from the head port to the log. You can then run a riser elbow system. These were on both lower profile lake style hot boats, and some lower profile salt water as well. Use exhaust flappers for waves and stern wake when coming off plane. Gtg.

It don't see where you're trying to inject the water...into the individual header pipes?

Hi Tartilla,

I’m trying to get away from the log manifolds. Too restrictive performance wise. I’m building a 355 with some performance parts. I’m running a performance intake setup and need free flowing exhaust.

I’m hearing the likes of series ‘V’ Cerakote can help suppress heat which would work brilliant. I would get them coated inside and out up to the copper piping that exists through the transom and flappers.

Thanks mate.

assume you are not in the States but here that setup is big NO. you can not run water injected headers in an enclosed engine bay and even without a cover that is close to the fiberglass sides and even with the water injection that setup runs pretty hot. I run injected headers but they are on my flat bottom with a fully exposed engine. I think you would be better served and safer for the engine with a fully jacketed exhaust. Stainless Marine or similar would be my choice.

Australia.
Thanks for your input.
I’m to visit a Cerakote applicator today. I have been advised by an applicator that this would be fine coated with series ‘V’ Cerakote.
I have noticed how close it is to the fibreglass but I also have the option of heat wrapping it if there is any issue. Although it isn’t fully open it will not use a hood.
I’ll keep you guys posted as to the outcome.
Thanks mate.