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Quote:

Originally Posted by pantera232 (Post 3510163)

What is your idea on this 3/8 fuel line should i go up to 7/18 or 1/2 inch ? BOB is telln me im not getn the fuel, im running a 23 mirage and getting 4800 rpm on a 24 pantera wot

3/8 fuel line will easily supply enough fuel for over 500hp.

Quote:

Originally Posted by Artate78 (Post 3509947)

Thanks for all the response guys. Only thing didn't want to run aluminum heads or intake. Salt water eats them up.

Get a Dart or Merlin marine intake manifold with bronze lined water passages.

Quote:

Originally Posted by MILD THUNDER (Post 3510205)

If you suspect running out of fuel, your spark plugs should tell the story.

Running these stock gm truck heads, your just not gonna make the power. A 454 is small enough by todays standards. To make power, you NEED to spin the engines. 4800, 4900, 5000 just ain't gonna do it.

Build them with cams, heads, intakes, and carbs that will support 5600-5800 and let them run. There is an abundance of cams, lifters, valvesprings, rockers, etc, that can support the additional rpm with no problems. Not that many options 25 years ago, so guys tried to make low rpm power reliably with oval ports truck heads, dual planes, etc.

Bob Mandera hooked me up with everything to spin 5300 rpm from valve springs to morel lifters etc, i have air gap intake, i had peanut heads and he recommended in my price range fining 781 heads he knew the entire build and said the motor should spin above 5200 rpm, i have the forged domed pistons with over 9:1. I understand where your coming from but others said 781 were best flowing gm heads, Understanding the smaller valves are effecting it.
At this point over the winter i could either have the head shop do the larger valves or find some merlin,dart heads and install all the guts.

Pantera, just curious what fuel pump are you running. You should at least be running something like this.
http://www.summitracing.com/parts/HLY-712-454-11/

Jim, it's a fuel pump run of belt, and attached to water pump, I also have a old electric one that I can switch
On at helm when doing high speed runs, is there a certain electric pump i should run.

Quote:

Originally Posted by pantera232 (Post 3510970)

Jim, it's a fuel pump run of belt, and attached to water pump, I also have a old electric one that I can switch
On at helm when doing high speed runs, is there a certain electric pump i should run.

I couldn't tell ya anything about the electric pumps.Never messed with them. Those pumps that run off the water pump, is there anything special about them or will any BB pump work. Have any idea of the specs of the pump that's on there now.

Can't see any specs running 7psi at idle, its a gen 6 block it's a nice setup if water pump breaks, I'm going to open up the tank next week and check pickup

Quote:

Originally Posted by picklenjim (Post 3511021)

The fuel pump that bolts on a BB block, will not work on a sea water pump driven fuel pump. The arm on the fuel pump is different. Think you need to go after mnarket.

Quote:

Originally Posted by pantera232 (Post 3510163)

What is your idea on this 3/8 fuel line should i go up to 7/18 or 1/2 inch ? BOB is telln me im not getn the fuel, im running a 23 mirage and getting 4800 rpm on a 24 pantera wot

I agree with Griff. You do not have to small of fuel line. I have stock 3/8" fuel line in my boat. I have 600HP 454's that I can spin to 6200RPM with no issues. I am not saying that bigger is not better, but I do not believe it is your problem. What does your fuel pressure gauge read at full throttle? Have you propped down?

I run Mallory 140GPH electric fuel pumps.

I'm running 7psi at idle I'm going to
Run it tomarrow and see at wot, prop is a 23 plus
I also have a 23 mirage fastest prop
For boat so far.