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Cuda
10-28-2006, 01:11 PM
I bought this carb off ebay. It's supposed to be a 750. I've tried to look it up by carb number, and I can't find the number on a Holley list anywhere. The number is 80466. I'm wanting to bolt it on to a stock 1982 330 horse 454, with a Performer intake, and Dana exhaust. I'm told the 1982 330's had the oval port heads as opposed to later 330's with peanut port heads.

Can anyone verify the 750 cfm, and what the stock jets were?

DONZI
10-28-2006, 02:48 PM
Ck. this old S/W thread Cuda. I know it's politically incorrect to re-direct to another site.But if it helps solve a problem, it should be important enough. Please forgive me Board Gods. I try to not do it often.There is a carb. part reference by Boatn70 on it.
http://www.speedwake.com/upload/showthread/t-25549.html

Cuda
10-28-2006, 03:08 PM
I had another person tell me it's the 800 cfm HP 500 carb, but I just checked the carb that I bought that was on the HP500 I bought, and it's numbers were:
SAEJ1223
9022
2873

:confused:

Is the 800 too big for the 454?

BigGrizzly
10-28-2006, 06:45 PM
I feel it is especially if the engine is a330 horse. the best way to check is bolt it on and put a manifold vaccum guage on the motor and run it WFO if vaccum is less than 3/4 it is too big. Vaccum should be between 3/4 and 1.5 inches at WFO. This is not up for discussion, If someone doesn't agree that is fine. I will not argue this point. Just rember I have been doing this a long time. Most of you know how my boat runs and idles. If border line go with the smaller carb

Cuda
10-28-2006, 06:52 PM
It was advertised as a 750 when I bought it. I knew a 750 wouldn't be too much since the stock Q jet is 750 cfm. You don't think the improvement in intake and exhaust would allow it to take the 800 cfm. The engine still has the old log style exhaust on it.

BUIZILLA
10-28-2006, 07:10 PM
why don't you just open both of them, and see whats in them and get back to us ??

BigGrizzly
10-29-2006, 06:17 PM
A 750 should not be too big. even if you changed exhaust I doubt the 750 would be too small. My Criterion 502 engine has everything in it and a blower and I use a 825 CFM. beleive if a bigger carb would be better all around I would have one

DON N.
10-30-2006, 04:28 AM
Wfo = ?

MOP
10-30-2006, 05:24 AM
What about the 750 throttle bore sizes, anyone have that measurement?

Cuda
10-30-2006, 06:13 AM
A 750 should not be too big. even if you changed exhaust I doubt the 750 would be too small. My Criterion 502 engine has everything in it and a blower and I use a 825 CFM. beleive if a bigger carb would be better all around I would have one
The question isn't if the 750 would be too small, it's would the 800 be too big.

Cuda
10-30-2006, 06:14 AM
Wfo = ?

Wfo= wide freaking open

Barry Eller
10-30-2006, 07:32 AM
I bought this carb off ebay. It's supposed to be a 750. I've tried to look it up by carb number, and I can't find the number on a Holley list anywhere. The number is 80466. I'm wanting to bolt it on to a stock 1982 330 horse 454, with a Performer intake, and Dana exhaust. I'm told the 1982 330's had the oval port heads as opposed to later 330's with peanut port heads.
Can anyone verify the 750 cfm, and what the stock jets were?


Hope this helps you.

Barry

MOP
10-30-2006, 10:07 AM
Hmmm 800cfm Joe sell it to one of the 502 guys!

Cuda
10-30-2006, 12:48 PM
I can't imagine 50 cfm making that much of a difference, hell the Merc 350's used to come with 750 Q jets.

Barry Eller
10-30-2006, 03:42 PM
I'm using the same 850 cfm that came with my OMC 454HO on my 502 now. The 454HO was 365 HP, only 35 more than your 330. My 502 is 470, I did have to enlarge the idle bleeds to compensate for the increase in vacuum.

BigGrizzly
10-30-2006, 04:24 PM
I don't think an 800cfm would be too big, may not be as effience. With the power valve system alot is selfmetered. My suggestion is try it. On my origional 330/454 my 650 double pumper was as good or better than the stock 750cfm. RTWI did work on jetting etc.

Cuda
11-01-2006, 08:59 PM
why don't you just open both of them, and see whats in them and get back to us ??
I opened up the one off the HP. I'd say the secondaries hadn't had gas in them for a long, long time. :(
Jets were:
Primaries 75 & 80
Secondaries 89 & 93

Cuda
11-01-2006, 09:04 PM
No power valve in the secondaries. The Holleys on my Formula have a power valve on both.

BUIZILLA
11-01-2006, 09:21 PM
put 78/frt and 84/rear in it with a 6.5 PV in the front, and try it...

:wink:

Cuda
11-01-2006, 09:28 PM
put 78/frt and 84/rear in it with a 6.5 PV in the front, and try it...
:wink:
For the 454?

BUIZILLA
11-01-2006, 09:30 PM
yuppers

Cuda
11-01-2006, 09:38 PM
Thanks!

BigGrizzly
11-01-2006, 11:06 PM
I'm with buz. We have taken several carbs apart from Merc HP500 and 540 and have found all sorts of configurations. One was just like yours but backwards big in primaires. Merc swears they didn't do it, but this one was in a crate, suposedly pre run yet looked as if no fuel had ever been in it and plugs looked like never run. Just for fun we ran it that way and beleive it or not it ran pretty well. However properly jetted and tweeled this 540 pulled another 27HP. If I hadn't seen it I would not have beleived it.

Cuda
01-31-2007, 07:16 PM
I just took this carb apart, and put the jets that Jim suggested in it. I didn't check the power valve, because I was afraid I'd tear up the gasket. Like the other carb that I know came off an HP 500, this one only had a pv in the front also. The jets in it were 79 in the primaries, and 90 in the secondaries, not staggared like the ones in the other HP 500 carb.

As soon as I do a test run with the exhaust swap only(to get a gps speed), I'll start on the intake/carb swap, that way I'll know what made the biggest difference. :wink:

BUIZILLA
01-31-2007, 07:41 PM
does that carb have the primary throttle blades drilled?

Cuda
01-31-2007, 08:29 PM
does that carb have the primary throttle blades drilled?
Not that I know of. Here's a picture of the bottom, with the primaries facing front.

mrfixxall
01-31-2007, 08:55 PM
Not that I know of. Here's a picture of the bottom, with the primaries facing front.

THEY STAGGER JETS THE CARB FOR A REASON IF YOUR RUNNING A DUAL PLANE MANIFOLD,ITS GOOD FOR XTRA HP...THE ONLY TIME YOU SHOULD USE STRAIGHT UP JETTING IS WHEN YOUR RUNNING A VICTOR STYLE MANIFOLD...AN OLD DUDE THAT USE TO RACE FOR KENNY BELL TAUGHT ME THAT ONE....


BUTTERFLYS NOT DRILLED,,IT JUST HELPS IT IDLE BETTER...

Cuda
01-31-2007, 09:01 PM
The staggared jets were for the Dart intake I think.

RickR
01-31-2007, 11:07 PM
Stock jetting on a HP500 carb w/Dart is

Primary Port 81 Star 75
Secondary Port 89 Star 93
6.5 Powervalve

d1mbu1b
02-01-2007, 07:26 AM
Hope this helps you.
Barry

I would suggest using Barry's data sheet and go back to the stock jetting.
78/84 is good advise since its safer to run rich but for a motor that only breathes enough for 330 horse that seems like an awefull lot of gas.
70-72 and 78-82 seems like a good starting pt.
The stock jetting is usually best.

I am going through the exact same thing right now.
I am not running correct yet, so take that into account, if you plan on listening to me. I will let you know were I end up with jetting.

I put a manifold vacuum gauge, A/f gauge, and fuel pressure gauge in the cockpit.
It is unbeleivable the amount of info you never knew was going on.



Vaccum should be between 3/4 and 1.5 inches at WFO.

Thank you. I have been searching for that info for a long time.


secondary power valve: I understand that when we want the secondaries open we want to be wide open so, no need for the secondary power valve.

The vacuum gauge will tell you where you want the primary power valve to open.

I run at 10 inches at cruise, so my power valve is currectly 8.5.
you cant know this unless you hook up a vacuum gauge.

hope this helps.

BUIZILLA
02-01-2007, 08:02 AM
who cares what the stock jetting is on a HP500 carb when he's using it on a stock 330 with a stock intake............

Cuda
02-01-2007, 08:37 AM
I would suggest using Barry's data sheet and go back to the stock jetting.
78/84 is good advise since its safer to run rich but for a motor that only breathes enough for 330 horse that seems like an awefull lot of gas.
70-72 and 78-82 seems like a good starting pt.
The stock jetting is usually best.
I am going through the exact same thing right now.
I am not running correct yet, so take that into account, if you plan on listening to me. I will let you know were I end up with jetting.
I put a manifold vacuum gauge, A/f gauge, and fuel pressure gauge in the cockpit.
It is unbeleivable the amount of info you never knew was going on.
Thank you. I have been searching for that info for a long time.
secondary power valve: I understand that when we want the secondaries open we want to be wide open so, no need for the secondary power valve.
The vacuum gauge will tell you where you want the primary power valve to open.
I run at 10 inches at cruise, so my power valve is currectly 8.5.
you cant know this unless you hook up a vacuum gauge.
hope this helps.
I'm thinking this 330 horse will flow better than the newer 330's because it has the oval port heads, instead of peanut port. Between that, and the new exhaust, I think it will. I do have a vacumn gauge I can hook up.

d1mbu1b
02-01-2007, 12:04 PM
who cares what the stock jetting is on a HP500 carb when he's using it on a stock 330 with a stock intake............[/SIZE][/B]

Because it is usually correct.
You dont rejet for CID.
You rejet for atmospheric conditions, and driving preferences.

Once it is set up properly (stock) it is pretty close for most applications.

Fuel flow (for main metering circuit only) is dictated by the velocity
of the air though the throttle bore at the boosters and the jet size.
(venturi, bernoulli)

The velocity is dictated by the volume of air (engine CID * RPM /2 (4cycle)) and the throttle bore area(diameter) (and booster diameter) at the boosters and time.
(CID/sqIn/t = inches/s = v)

since the throttle bore does not change the velocity is pretty much linearly proportional to volume, this means that a/f ratio remains constant.

simply stated a properly set up carb for a HP500 reving at 2000 rpm will flow just about the same volume of air, the same velocity, and the same mixture as a 454 reving at about 2200 rpm and a 350 reving at about 3000.
that is why you can take any carb and get it to run on any engine.
Because a/f ratio remains pretty constant.



Furthermore, jetting works in conjunction with the power valve cross sectional area in the metering block which is not easily changed.
Some are set up for lean at cruise rich wide open. or rich/rich.

You can't willy nilly change the main jets without knowing where your starting out.


Again, thats why you want to go to the stock baseline before tinkering.

BUIZILLA
02-01-2007, 12:10 PM
so what your saying is the 170hp difference of the two engines, rpm rating difference, and intake manifold construction, design and runner length doesn't make a difference........

I quit.......

JH