Well think I solved the mystery of my uh-roh stuck valve, looks like exhaust manifold on one side had a crack and some water was getting where it did not belong. So here comes the $100K question and I would appreciate any opinions.
What kind of experiences has anyone had with different exhaust choices. Presently I have stock Mercruiser manifolds/risers with thru-hulls on a carb'd 450hs/502 engine. Different options I have looked at range from stock Merc, Moore Perf', Rex Marine Powertorques, Stainless Marine, Gil etc...
Such a variety of claims from all the different makers, some just promise increased performance some promise 4-6 mph (sure) my biggest concern is a quality piece that will keep water where it belongs, second would be performance difference if there is any with a basically stock engine.
Thanks,
Rick
Guess what I am wondering is if it is worth spending the extra money considering my stock engine when comparing say the pieces that D.Moore's company makes compared to say Stainless Marine or Gil's. The Moore's look like they are a better made piece than Mercruisers. That's why I was looking for opinions.
Thanks again,
Rick
lightning headers (http://www.boatheaders.com/headers.htm) go here these are the best
Would these be overkill on a stock 502? And how do they hold up in Salt?
THOSE WOULD BE KILLER ON A 502 AND THE SALT WATER SHOULD NOT HURT THEM IF YOU TAKE CARE OF THEM DRAIN AND FLUSH
THOSE WOULD BE KILLER ON A 502 AND THE SALT WATER SHOULD NOT HURT THEM IF YOU TAKE CARE OF THEM DRAIN AND FLUSH
Price is only a couple of hundred more than Stainless marine's manifolds so not too bad there. They also claim to expect 45 hp gain or 300-400 rpm increase- anyone have stories that worked out that way.
Thanks guys!
If you decide on Lightnings, I would not recommend the dry tailpipe option. Turns out it's anything but dry. BTW I have a set that I'll sell cheap to anyone that wants to try them! I had problems getting the slip joint between the collector and tailpipe to seal properly because they weren't perfectly aligned with the transom holes. Maybe someone else would have better luck. It's a mickey-mouse setup as far as I'm concerned. The standard Lightnings with the long collectors that use the normal rubber hose connection to the tips are probably a better choice.
I just installed a set of Stainless Marine Gen III manifolds. They run about 2500 bucks from CP and for that price you get custom s/s tails that are jacketed all the way to the end, past the transom. I was extremely impressed at the quality of these manifolds. There are no water connections that can leak into the exhaust, and the v-band clamps for the manifold/riser and riser/tailpipe connections are just about idiot-proof. I haven't had a chance to run them at top speed yet so I can't compare performance to the Lightnings.
-brian
From my past experience, the quality of the Stainless Marine products is top notch. I had an older set on a pretty mild 468 and they were very nice. As Doghouse indicated, water doesn't pass through any gasketed areas so there is no chance for leakage.
I currently run Lightnings and they do flow better than the Stainless Marine deals (different motor combo so hard to say how much), but I would not run them in salt water unless they were the stainless interior/exterior pipe deals. The standard $1600 stainless interior/mild steel exterior tube deal just won't hold up that long to saltwater use. Yes proper flushing will prolong their life, but sooner or later the internal coating on the mild steel will give way and I don't think that 16 gauge steel will last too long when exposed to salt water.
As far as the increase in power from the aftermarket exhaust, remember that exhaust systems either support or hinder power, but they do not make power. In other words, if your mill isn't flowing the air to begin with, better exhaust won't be doing much to aid the situaion.
my .02
Chris
I'd go with the Stainless Marines. They have an outstanding reputation for durability in salt
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