Edelbrock carbs are just fine. I'm one of the nay sayers here when given a choice, but they truly are just fine!

Biggest thing is no one knows how to set them up and run them properly. Well, near no one. They are, for the most part, the old Carter AFB carb. The same carb used on the '63/'64 Superstock Dodge/Plymouths, the same carb used on the '64/'65 Superstock Pontiacs, and the same carb used in '66 to '71 on all Street and Race Hemi engines Chrysler made. Intake manifolds varied, mind you.

The biggest thing, as Omar said, in KNOWING how to tune one. Adjustable jets, linkage adjustments on the secondaries, idle, and high speed, mixture available at the turn of a screw....yeah, Holley guys have no idea how to handle that........... 

Ray

I'd be with GT on this. 21', open bow, great pleasure craft, that does 55 MPH....I'd leave the focker alone and maintain it!!!!!

First, maintain it and keep it working, you see the threads on here how many of us are rebuilding or blowing $hit up???

A 21' heavy ass, open bow, boat to your target MPH is a VERY big order. And you're gonna burn through equipment to do it like I burn through a bottle of "Cabo".

Can't get half nekkid, bikini-clad women in a non-running boat in the driveway...............

Ray

LOL, funny you say that. My truck is the only thing I own that is stock... Here's the stupid part, I bought it brand new in 2005 and it just turned 32,000 miles, has been switched over to synthetic oils and the only thing I changed on it was replacing all the speakers, adding an amp and installing a 40 gallon auxiliary fuel tank. Oh yeah, and a Hoola girl on the dash...

My Blazer had a bumper sticker that said "Stock Sucks"...

GT

8 years old and only 32,000 miles? Drive the thing man! I know people in town here that have more miles on newer Jazzy Scooters....... 

Ray

Get with my oldest Daughter (me for her contact info). She's in Greensboro and knows Charlotte pretty well. Might help you out a bit....or not....she IS my daughter after all!   

Ray

It's a holley 750, possibly an 850, mostly stock motor.  Secondaries open and they are vac. MSD R2R with a blaster SS coil, no balast resistor.  I doubt it is 180 out because it doesn't run bad at all, sounds really good actually.  I'm gonna check fire order in the morning.  I have 3/8" fuel line, it goes:

Tank pick ups to manual selector valve
Selector valve to fuel/water separator (1 week old)
Separator to mech fuel pump with new filter inside

I need to replace the fuel lines from tanks to the selector which I will do tomorrow, have new Gates reinforced fuel injection lines already. Coworker suggested if the lines are old or not the right quality they can suck themselves shut and restrict flow, and that is why all boats have upgraded fuel lines from automotive applications.  I won't be able to get it on the water again until sunday though.

If it was 180* out you would know it. A couple plug wires in the wrong place, that's one I wouldn't have thought of, but worth a check. Seen that on U-Haul trucks in the past.

I'm going with the concensus that the tach is snafu. Or it's incompatible/not set up correctly with your ignition, something. 51 MPH out of a pretty heavy 19' Hallett does not equate to 2900 rpm on a stock 320 HP engine. Just not buying into that.

Also, on the hose, remember you are not loading the motor. A Jet Drive, IN the water, acts, for the most part, the same way a dynamometer does to measure crankshaft HP. The jet drive, for the most part. (I know, some of us are hitting them with 6-7-800 HP and a few well beyond that, but that is an entirely different matter). The motor is gonna quit before the jet drive does, if the jet is in decent shape. More RPM, more resistance to the engine at an exponential rate. This is why you can almost look at a Berkeley Impeller chart and find your impeller, and your max RPM, and be pretty darn close to what a dyno would tell you your max HP is AT that RPM.

A standard, marine 460 is a 320 HP deal, and usually an A impeller in the pump SHOULD let you spin up to 4600 or so RPM. My old 21' Biesemeyer had a fairly fresh, new, Harmin Marine 460 and JC-A and would spin to 48-4900 with no problem. A whopping 50 MPH.........Mind you....... Only mod was an 800 CFM carb.

I'm not saying your boat is as heavy as that old tank was, but if you're pulling 51 MPH at 2900 basically stock, we are ALL doing something WRONG!

Running the boat on the hose, you are only trying to cool the motor, and hopefully you're stuffing a hose both up the intake and up the wazoo to lubricate the pump while doing this! What is going to happen doing that is the motor is free-wheeling and will spin up to whichever gives up first, the ignition or the valvesprings.  Means nothing about where the power is, or where the problem may lie. Particularly with a Vac Sec'y carb (Which I am in the minority of being a fan of). 

Keep these things in mind playing with this thing. 

Ray

Actually, you don't have the worst flowing heads. The D3's are usually fine and can be ported to near ridiculous numbers if you want to do that. The C8/C9 D0VE heads do have larger intake ports and no thermactor humps in the exhaust ports (Some D3's don't have those either), but they also have smaller combustion chamber volume which will bump up compression ratio without changing pistons, another plus, unless you are changing pistons anyway.

Honestly, I've seen some pretty powerful 460's running not so modified D3 heads, and I agree you're gonna get more bang for the buck doing what Ralph and GT said. First thing is to get the RPMS up to the 5000-5200 range to get the pump operating in it's optimal range (Sounds to me like the pump is fine, loading the engine up quite effectively) and that dinky carb is likely the biggest culprit that is mostly killing you. Go with an 800 at least or an 850 better yet. Hell a 750 would help a lot, but that's really too small!

Your intake is really the best dual plane available for the 460, so you're good there. The RV cam isn't so bad, but it's designed to throw the torque curve into the lower ranges rather than higher which would be optimal for a Jet Boat. Still probably better off than the standard truck grind.

Gotta be kinda careful just throwing cams at these things. I've seen and heard great results with the Comp 286, 292 and 305's, but the rest of the valvetrain has to be up to snuff, and geometry carefully checked when doing it. By that I mean screw in rocker studs (If the heads are not already equipped), guide plates, GOOD chromemoly pushrods, valvesprings and retainers rated for the particular cam/lifter set up you plan to run, etc. Valve spring seats may need to be machined to accommodate whatever valve springs are required as well.

Personally, we're in the season now! I'd leave it mostly alone, save for the carb, Place Diverter and ignition recommendations thus far for the time being. Be plenty of time over the winter to tear into the engine for more HP/speed if need be for next year. You've a better idea what is really going on by then also. Run it and have fun!

The D9 blocks, Ralph is correct. Really just a change from internal balance to eternal allowing smaller throw weights on the crankshaft. This also means the bores go further down into the block, which I don't know that there's a plus or minus either way. Just don't mix up the crankshafts with older cranks. I've not heard of any cylinder wall thickness differences or anything, just an issue with certain stroker setups not working with the '79 and later blocks. 

Ray   

All you need to do is obtain a foot throttle setup and potentially a longer cable.

This is very common on cruiser style boats and fishing craft.

You could potentially re use the shift portion of the existing control, but may opt out and use a more common Morse style.

You need a throttle assembly that is compatible with the 3300 (or old Morse 33C) style cables.

You could probably sell your existing control for enough money to change your stuff to what you want providing you go used.

Try to sell your existing control up north. Oregon/Washington area.

Good luck

X2, I have one that has 4 cables to it (Kinda weird and even Morse didn't know what it was, twin jet deal). Pretty common, really. Nordic454 had one. Basically the engine is in idle in "N", reverse bucket about halfway, then revs up and opens the reverse bucket at the same time in "forward", also revs up and fully closes the reverse bucket in "reverse" is how it's supposed to work. They are sorta sought after outside the Southwest here.

Ray

I was thinkin bout puttin a launch ramp for pile o shit bikes lol and to fill it theres a fire hydrant conveinently across the street

One thing, Mom has a couple large ponds back east (probably 25-35 feet deep about an acre each)  and the damn things used to grow weeds like CRAZY and FAST making boating/fishing, even canoeing, well, impossible!

White Amur's are your friend there! (commonly known as Grass Carp) You can get them sterile or not. Sterile, you'll hafta replace them every year, maybe two if lucky. If not, you'll probably hafta work out a means to speed and replenish weed and grass growth. Otherwise, the same as the Sterile ones. 

Ray

PS. I should add, we never had to replace them once Pops put them in. He had all sorts of peeps "live welling" bass, perch, bluegill, etc in so the pond was pretty self sustaining and no weeds. Made for good fishing too with kids, and grownups alike! Dad only let them keep Bass over 24" and very large Crappie and Bluegill, but on an honor system. 

ROFL!! 

Ray

Well, Happy Birthday John!!!   

Ray

Happy Birthday Chromey! Arrrrrr!

Happy Birthday Sergio! Que Pasa?

Happy Birthday MY Baby Gerl Becca! OK, Yu-Gi-Oh is childish but Anime is cool now? sheesh!

Happy Birthday Daniel (Willowog)! Kinda scarce these days, ain't ya?

Happy Birthday Baby Gerl Crewcheif, Becca, Yesterday, but can't ignore her! I know, I call you the other Becca and your dad calls mine the other Becca.

Are there ANY MORE BIRTHDAYS today?

Amazes me every year there are so many on, and around this date with this group......

Ray

The one I got sitting out back here is Fiberglass......

Ray

Every time I let get passed the "sign here" stage, I'm screwed...so I try and be proactive.

Running around in my '71 Nova (BBC, 4 spd, loud, etc...). Pulled out of a parking lot one night and got into it till the top of second, then owed and took a turn in my neighborhood....at which point I noticed half the city's police force behind me lights a blazing.  My chick in the passenger seat was laughing so hard she was about to hurl....for whatever reason, I had a smile on my face when the officer walked up and asked..."do you know why I pulled you over?"

ME: yup, right tail light out, left brake light out, too loud, too fast one headlight dim, mighta chirped the tires, big monster tach obstructing my vision.....  At which point he said " slow down, I can't write that fast"....he told me to take it easy and let me go after we laughed about it for a minute.

I had a similar thing back in HS, lol! I had a '73 Nova SS, in primer and vinyl top, was never a pretty car when I owned it,  with a tunnel rammed 427 I got from a truck, 4 speed, extended spring shackles and air shocks to clear the M50 tires, etc. Coming out of the movie theatre at the new Mall in town (farm country, middle of nowhere Pennsylvania folks) at about 11:30 or so after the movies let out I was following a bud of mine who had a '70 Torino GT (351C, Auto, BAD ASS CAR!) He did a "stomp and squirt" around a corner. I decided it was a good time to show him what real HP was (back then).

So I land on it, and hold it, smoke everywhere, and pull up behind him at a stop sign. It was just THEN I noticed the red and blue lights reflecting off the wall at the Sears end of the mall. I couldn't even see out the back of the car it was lifted so, let alone the tire smoke.

Girlfriend in the passenger seat, Statie comes up and asks "what was that display of HP all about?". "Just Showing off I guess sir, sorry". "You know that's a $35 fine right there" as he pointed at the fuzzy dice said girlfriend hung on the rear view mirror earlier the same evening. Took them off quickly and tossed them into the back seat. He said "Obstruction of vision with all that sticking out of the hood isn't it?". I was at a loss, and all I could come up with was "Probably no more so than the radar equipment on the dash of yours".

He actually laughed and let me go.

But kinda my point. Cops today would NEVER let you go for stuff like that. Too much money on the table they could collect.........

PS, My Nova had as loud a stereo as an 8-track could be back then Pat.........Blasting "Lynrd Skynrd"........ Also, If I remember right, The date I took was to see the movie "Porkies" when it came out..........