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Does anyone make an affordable LS exhaust manifold yet? |
I’m dying to see a 650+ 454 cu in engine live in a boat. There is someone in the swap shop and on Facebook selling a pair of LS marine engines. Think they were in a sunny. Might be a good person to talk too here it is https://www.offshoreonly.com/forums/...otors-25k.html |
Originally Posted by Crude Intentions
(Post 4656355)
I’m dying to see a 600+ 454 cu in engine live in a boat. https://www.offshoreonly.com/forums/...otors-25k.html I ran 600HP 454's for 6 yrs with no issues.(cruise@4800 RPM, 6500RPM@WFO) I then detuned them to ~550-575Hp for another 5 yrs. Fully refreshed them this summer and I run 87 octane. https://www.offshoreonly.com/forums/...otors-25k.html And Dennis's engines are a good package. |
Interesting. N/A? I mean naturally superchargers would live. If N/A please share the specs and do tell what exhaust you ran. Also I will correct but I meant to say 650+. |
Originally Posted by Alwhite00
(Post 4656354)
Does anyone make an affordable LS exhaust manifold yet? |
Originally Posted by XtremeCFM
(Post 4656317)
Hey guys, i have a scarab panther 30' that i have the twin 454ci motors out of it, i was going to build them up NA to make about 680ish hp.
Originally Posted by XtremeCFM
(Post 4656342)
combo would be basically 11:1, hyd roller cam (thinking something in the 234/242ish), aftermarket alum heads (ported), leaning towards dual plane intake with hp950 carb and dry exhaust should do it
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680 is a stout number for a NA 454/468. Your asking for almost 1.5hp per cubic inch. I doubt that setup will be very user friendly.
Most marine high performance endurance builds, are usually in the 1.0-1.2hp per ci range. I certainly dont see 680hp with that cam, dual plane intake, and marine exhaust manifolds. At least not on a dyno thats actually calibrated. |
Originally Posted by MILD THUNDER
(Post 4656412)
680 is a stout number for a NA 454/468. Your asking for almost 1.5hp per cubic inch. I doubt that setup will be very user friendly.
Most marine high performance endurance builds, are usually in the 1.0-1.2hp per ci range. I certainly dont see 680hp with that cam, dual plane intake, and marine exhaust manifolds. At least not on a dyno thats actually calibrated. |
Originally Posted by compedgemarine
(Post 4656415)
you just have to use the right correction factor and they make all you want.
that seems the way to do it here. Awesome power claims but boat is no faster than another one with a 500efi. Of course they have all the excuses in the world as to why it isn’t as fast. Lol. |
After doing the 600HP to now ~550-575HP my boat is faster with less HP. I believe this is because I brought my pk TQ and HP down and closer together. I couldn't believe how far the splits would be on a 680HP 454. When cam testing in the race boat the highest HP dyno "King" camshaft wasn't always the best or fastest in the real world boat.
Oh, and my 454's are so far 4mph faster than the 500efi's that were original to my boat. |
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