New Carburetor

Hi all.. I am going to buy a new holley carb for my 78 SN. 351 Windsor..

I am looking at a conversion holley made at National Carburetor.

The new conversion(shown in the pictures) are built from a new Holley 0-80457-SA, and has been completely converted to a 0-80319 Marine unit using all new Holley Marine components to make this unit US Coast Guard compliant.
By doing this conversion we can offer this new light weight aluminum unit for hundreds of dollars less.

Has anyone purchased one of these?

Thanks
Eric

Never mind

I guess nobody wants to answer the question you asked

They just want to recommend a QFT M-600 instead.

Looking at the prices, you'll be paying 450 plus shipping for the converted carb from National or you can easily find the QFT for 495 with free shipping..

Myself, I don't have any experience with the conversion carb and for the little bit extra for the QFT, this should be almost a no brainer to go with the QFT.

They've been around a while and have a good track record.

Of course somebody will probably ask why you can't rebuild yours, get it rebuilt or buy a rebuilt Holley if you want to save some money, but based on previous posts it looks like you have a 450 Holley and want to put a 600 on it.

A 450 would not be appropriate for a 351w, the 600cfm would have been original equipment.

Eric Harrell wrote: I pulled my boat out last summer when i found out I had wrong carb..this is realy the only issue I have fought other then general stuff.. So what is a QFT....and where do I buy one??.. Just want to make sure it works for this boat Thanks for the help Eric

Quick Fuel Technologies,, You can find them at Summit, Jeg's etc and the price seems to be 495 bucks with free shipping.

Look at the Quick Fuel web page for info too.

Here's a link to the 600

link

You'll need a new fuel line with the QFT carb due to the bowl design.

KENO wrote: Here's a link to a thread with fuel line info and as it mentions in the thread the flame arrestor may or may not clear the external float adjusting screws depending on you flame arrestor. link

Good info Ken, a simple spacer below the arrestor would clear the float adjustment if you run into that issue. Other than that and the fuel line every one I have installed (besides one that was warrantied) will almost run just right out of the box with no tuning even down to idle RPM. Bolt it on as it comes out of the box and see if it will run then tune one part at a time from there. In my experience you can't get the front float level to the middle of the site glass (probably due to engine angle).

The throttle response is fantastic and the cold or hot starts are nearly like EFI when tuned correctly. You won't regret spending the cash on one of these.

I'll agree with the Quickfuel. I did a rebuild on my old Holley after having an issue running way too rich. Needless to say the rebuild didn't do a damn thing to help and I've struggled since then. Finally got tired of beating my head against the wall and slapped on a M600. When folks say it works straight out of the box they ain't kiddin! I've got a Holley doorstopper if anyone needs one.

U used National years ago. Rochesters. One the did perfect, the other they did not.   Had to return a couple of times then wound up fixing some of the external errors myself.   

Duane in Indy did a spacer on his 302

Halfway down page 3 of this thread

shierh wrote: Holley tech guy said I should use a wedge spacer.   they have 7 and 12 degree, any of you use one?

Most cars are set up with 5* of angle on intake manifold    Most boats are set up with 15* of angle.    Do the math. 10* angled spacer would be about right

WinterTurtle wrote: Duane in Indy wrote: Most cars are set up with 5* of angle on intake manifold    Most boats are set up with 15* of angle.    Do the math. 10* angled spacer would be about right I'll be reassembling my Holley this week and remembered this thread while I was staring at my intake on Saturday. Is there a consensus on how important / beneficial angled spacers are for the PCM application?

Sounds like it didn't have a angled spacer originally. How has it performed without one?

KENO wrote: It's run for 40 something years without a wedge but some people like to run it more level with a wedge. Personal choice whether you do this or not

Duane in Indy wrote: Boats are set up using automotive intake manifolds which are milled at 5* as previously stated. Auto engines are set in at about 5* and then the intake angle of -5* puts the carb back level. Boats as stated are set in at 15*. That puts a lot of angle on the carb base as you have seen on yours.   As others have said "personal preference"     I prefer mine level. Floats are then set up properly;. Your choice edit   added pic .

Duane in Indy wrote: Most cars are set up with 5* of angle on intake manifold    Most boats are set up with 15* of angle.    Do the math. 10* angled spacer would be about right

Duane,
OK, I'm struggling with the math! How many degrees do you add for the pitch of the boat when it's underway?    Many of our hulls including yours run bow high. That no longer puts the carb level.

[QUOTED] OK, I'm struggling with the math! How many degrees do you add for the pitch of the boat when it's underway?    Many of our hulls including yours run bow high. That no longer puts the carb level. [/QUOTE]

Bow position depends whether I'm in forward or reverse.

Just leave it stock and you'll be fine If it gives you trouble later then shim it
Get it back in the water and have fun

Duane in Indy wrote: edit   added pic .

Duane- Your studs look quite plumb to the carb mounting surface of the wedge. Did you rebore the the stud holes while you had the manifold in the shop? I am wondering if there are any easy ways to correct stud angle.

Some people have rebent the original line enough to fit.

Some have used USCG approved A1-15 rubber fuel line.

Sierra sells a couple

one is part number 18-8115 it's 25 inches long

another is 18-8114 and it's 31 inches long.

Or you can make your own out of the same A1-15 hose or bend up some 3/8 tubing.

Here's a good link with links to the coast guard regs and the ABYC talking about fuel systems.

link

You might notice that Pete did some learnin' about USCG regs in the linked thread