Carb Question...
 

Hey All,

I have a 454 that was converted to an HP 500.

It has a Holley 4150 850 CFM on it, that went to ****
this past weekend. Blown power valve, float adjustment adjustment is stripped right out of the bowl. :eek:

Long story short, I am looking for a new carb...

Can anyone suggest a carb that will be pretty much set when I bolt it on..?

I understand that they are (Can be) difficult to dial in..?

Please let me know...

Thank You,

Jim

A Holley 9022 800cfm should pretty much be bolt on and go. It may some minor tweaking, but the stock jetting should be very close. That is the stock carb used on the HP500.
The 850 you had was on the large side for a 454.

Can you tap/rethread the the float adjustment? Just an idea....

I just put a marine edelbrock on mine, perfect right out of the box and they are very easy to adjust if needed

or just buy a replacement bowl and a new power valve. Shouldnt cost much, maybe 50 bucks. The HP500 was a a 502 engine. The HP450 was a 454. Really no way to convert a 454 into a HP500. But you can make a 454 into a HP450 with the proper parts. The HP450 pretty much used the same cam, intake, carb, heads, ignition, etc as the HP500. Just different blocks.

Stock jets in the HP 450 with the holley 800, were staggard. They used #75 and #83 in the primary, with a powervalve. #89 and #90 in the secondary, no powervalve.

Now, if you are planning on saying the heck with it, and just want to buy a NEW carb, I'd call Patrick at Pro systems carbs. Its really not much more $$ than a off the shelf holley, but the carb will come with nice hardware, and tailored to your engine. Bolt on and go. Like griff says, stock 800 jetting would probably be close though with a stock holley 800.

I was considering buying new dominator carbs this year. They were roughly 950 bucks each from summit. Prosystems dominator, built for my application, with all nice pieces, were like 975 bucks each. No brainer.

Or call Nickerson. I did and am trying to decide if I am going that way. He told me 499.95 plus parts to rebuild my carb and he says they can rebuild anything no matter how bad. He said it will be set up for my particular motors and will have a lifetime warranty. He said if you ever change anything on the motor he will adjust the carb to go along with the changes. I have 454's with holley 850's and he said that 850's are not to big for 454's. Does anyone have any problems with Nickerson?

I have no experience with Nickerson or Pro Systems but If your considering spending $800-$1000 I think you owe to yourself to do some research on Willy's carbs..they are very nice pieces IMO..you can change the jet size with the turn of a hex nut on the side of the metering block..he will build it and run it on a Dyno before he sends it..anyone else on here have any experience with them?

I strongly suggest that you save a few bucks and bolt on an Edelbrock Marine Carb 750 CFM.

Once the air/fuel mixture is correct (it will be very close with the Edelbrock) there is no difference between the 750 CFM of the Edelbrock carb and the 750 CFM of a (so called) improved/expensive carb.

If the air/fuel ratio is correct, your finished. There isn't much that can be done to improve the performance of a modern carburetor!

Modified carbs are for people who install MSD ignitions and special electrode spark plugs (they also buy snake oil at the county fair!). They must have a lot of money to waste...
Dennis Moore

I put the 750 Edelbrock on mine almost perfect right out of the box and jegs.com had them on sale

[QUOTE

Modified carbs are for people who install MSD ignitions and special electrode spark plugs (they also buy snake oil at the county fair!). They must have a lot of money to waste...
Dennis Moore[/QUOTE]

I have no experience with the edelbrock carbs. I notice they are spreadbore design. Any idea's on how much HP they can support in a 750CFM? I mean I know they flow 750CFM, but, can the fuel bowls keep up say for a 500 horsepower 5500RPM marine engine? Will they starve for fuel in big waves? Are they tunable with powervalves? Do they offer 4 corner idle circuits to help with long duration cams around the docks?

They seem like a great carb for a 454/330, 454/365, or similar. Just wondering how they would do on a 500HP long cammed 454. And if one was to purchase a small blower down the road, like a 177 or 250, can he bolt a spread bore edelbrock on it?

My opinion would be to keep the Holley and fix the bowl and be done. The good old Holley DP carb you have will do anything you want it to. Whether you add more power, a small blower, etc. Easily tuneable, and replacement parts are usually a 5 minute ride to any autozone, advance, pep boys, should you need a gasket, powervalve, needle and seat, etc.

+2 for Patrick at Pro-Systems, just bought his 940cfm 4150, it was $970, tweaked and wet flowed.

The main problem with Holley four barrels is the needle and seat. They are at the top of the bowl and exposed to air. They will dry out after sitting the winter. The next spring they will not seal when the engine is started and the floats will overflow. New needle and seats every year.
A Quadrajet carburetor has the needle and seat in the bottom of the bowl. It is covered with gasoline all winter and remains moist. If you use a fuel stabilizer the needle and seat works fine the next spring (and many springs after).
Rebuilding a Holley is a crapshoot because the metering block can get plugged with debris or varnish and there is no way to clean it out unless you remove the welch plug.
Plugged metering blocks are the main reason why there are so many used Holley carbs sitting in the junk pile!

A Holley carburetor will shoot too much raw fuel into the engine every time the throttle is opened. This washes down the cylinders of oil, will cause premature wear to the rings and dilute the crankcase/oil with raw fuel. The diluted oil will wipe out the cam lobes on a flat lifter camshaft.
A Quadrajet or Edelbrock carburetor has a cup style accelerator pump with a slot in the pump bore.
Fuel will bleed off (back) into the float bowel when the throttle is opened slowly.
Smaller pump shot.

If the throttle is opened quickly less fuel will bleed off into the float bowel.
Larger pump shot.

Holleys have a positive displacement accelerator pump and once the pump shot volume and duration are adjusted (pump shooters and pump cam) the same amount of fuel is shot into the engine whether the throttle is opened slowly or quickly. This makes for a very rich air/fuel mixture when slowly maneuvering around the docks or at the launch ramp.

The square bore Edelbrock has twin float bowls and twin needle and seats and is the same carburetor (Weber four barrel/Carter AFB) that Mercruiser used when they could no longer buy Quadrajets from GM. It is important to realize that Mercruiser chose the Weber Four Barrel over the Holley Four Barrel for installation on Mercruiser Sterndrive engines for reliability issues.
Dennis Moore

Probably wouldn't be worth the money on a basically stock engine, but a Willy's carb will get you an extra 25-30 hp on a race engine. I have seen it in person. 430ci SBC 700hp engine, they added 20hp just by bolting on their carb, another 15 after some tuning. Very nice people and products.

Interesting...however anytime I read something that seems as biased as your opinion against Holley's it makes me wonder what's the motive for the bias. If Quadrajet and Edelbrock carbs are so much better than Holley carbs...why do so many performance builders use Holleys? Is it because Holleys are tunable to specific apps and the others aren't? Just wondering.

Most mechanics who work on customers boats are biased against Holleys. If you own "A" boat it is pretty easy to say that your Holley is a pretty good carb but when you work on 50-75 boats a year you soon develop a real disliking for Holley carbs.
When I attended one of the Mercruiser service training schools in the mid 1980's (Mercruiser mechanics must attend a service school every two years to remain certified) we were asked our opinions on what carb should replace the Quadrajet (GM was discontinuing the Quadrajet). Overwhelmingly every mechanic said anything but the Holley.

As a side note, everyone was asked about Ford marine engines and they got the same negative answer.

The love of Holley carbs is generally only shared by people selling them and people that DO NOT repair customers boats for a living.

Maybe there are some engineers working on engine projects in love with Holley carbs but anyone with practical experience, performing service and warranty work on a regular basis (for a living) is not very partial to them.

When I was building small block Chevy's, I loved the Q-Jet. Always ran great, easy to set up. It's hard to find a Q-Jet that will flow 940cfm though. If I wasn't looking at so much money I would have gone EFI. The cost of the EFI and new headers with O2 bungs put me over the top.

well i like all the carb . but when you make more power you need to use a a/f box to set the jets up . i had my motor dyno had more jet in it .put a a/f box on it i was in the 11. no good i am now at 12.7 at 3000rpm and 12.5 wot.your boat is the real dyno

Dennis...I'm not pro-holley...:party-smiley-004:...actually, I don't know enough about carbs to be pro-any-carb...just wondering where you were coming from with the Edelbrock-vs-Holley thing. Except for a couple of AFB's in the 60's all my cars have had Q's on them. My one other I/O had EFI so this is my first boat with a Holley. It has a Holley 4150HP, 850cfm on my Gen VI 502 (mild-build). If I wanted to go to a Edelbrock for whatever reason...which do you think I should consider and would my intake have to be changed?
Thanks

The Weber 4 barrel is sold by Edelbrock and is known as the Edelbrock Square Bore. You can use the existing intake manifold. For absolute reliability this is only second to the Quadrajet.

The marine Edelbrock Square Bore carb has a max flow rating of 750 CFM and is excellent for boating.
When the engines air intake volume is calculated in cubic feet per minute (that would be the maximum amount of air an engine can ingest in one minute with 100% efficiency) a 750 CFM carburetor calculates to the CFM rating needed for a 502 engine running at 5200 rpm. Engines never obtain 100% efficiency so 750 CFM is more than enough for your application. By NOT overcarbureting an engine, fuel mileage and low speed torque is maximized.
Dennis Moore

Oh my gosh Dennis.

Please put in your posts that it is of your opinion of Holleys vs Edelbrock and such.

If the carburetor tuner does not feel comfortable tuning the carburetor at hand, that does not make the carburetor bad.
I many times make the statement that the best carburetor for one to get is the carburetor one knows how to tune the best.

I prefer Holley's for performance motors because I can tune them the best. For stock motors, the Eddie's are fine because they are very close out of the box.....if the customer so desires. Again, this is my opinion because of my personal skills/knowledge/ and etc.


Anyhow,
Many of us are here because of performance motors.

How many Edelbrock's / Weber's are on the Blue Motors ? IE: The Mercury Racing High Performance motors ?

Also in my opinion and experience the CFM mathmatics you are showing is old school Holley textbook. Things have changed with more modern cyl heads, camshafts, and of course carburetors themselves.

As example: many times I'll and others will go 120VE% or more on that 'cfm carburetor math' on performance dual planes.

As far as Prosystems, Willy's, and etc, if you call them on a near stock motor I guarantee that they'll tell you to run 'such and such' stock Holley. Guarantee ? Yup, I have personally and have had customers call on near stock and also mild performance engines and that's what they'll give you for an answer.

Now, very high performance engines ? You bet ! There is more to changing fuel curves than jetting, PV's, step up springs, rods, and etc.

Anyhow, I'm saying the above as we would be talking having a conversation.

Just don't want this thread and info to be a one sided opinion.

:D

sb do you live on the east coast, i have a holley 650 dual feed electic choke, just had it cleaned do to bad fuel and now i cant get it to run right, it is runnig very rich ,its on a small block chevy about 380 to 400hp thank you

I remember the days Holley carbs and Cragar rims were the thing to put on your Hot Rods, not Quad's or anything else stock. Started to feel a little sick about my Holley on the HP500. Thanks SB for pulling me out the gutter. I actually googled eldeborock carbs, starting to look at prices. I'll stick with Holley, back in the day I would rebuild the Holley myself on my 69 Barracuda.

Could be anything from a stuck needle and seat, blown power valve, too high of float level, improper idle mixture or idle speed adjustments.

For a stock engine, I always loved quadrajets. I can't complain about my holley dominators. They sit on top of blowers, with long duration lumpy cams, and idle and perform like efi. Only difference is I have to pump the thorttles twice to start them if they sat for a week. No chokes, pretty much all out race carbs, and they flat out work.
:coolcowboy:

Yes, is that bad ? LOL.....just some east coast vs west coast humor. I'm actually in New Hampshire. On the big lake - Winni. Oh, now the big slow lake. :traurig001:

no not at all sb, i live in ct and have friends who live on the lake that work for clean harbors in bow, if i ever need a carb rebuilt i will keep you in mind:drink:

Thank you very much and I appreciate your response.
I can't help but to feel that the people that post on this forum all have very high dollar engines powering there boats.
BUT, every post has thousands of viewers (that never respond) and are just regular boaters looking for
simple performance tricks.
I will admit that with the slow economy and the boating business all but dead, I am on this forum to help promote my business (as are you).
I need to give very common sense advice to my perspective (regular boater) customers to give them the confidence that when they deal with my business they can trust me to be a straight shooter. I need them to feel that they can modify a stock marine engine for more performance without spending an arm and a leg for high dollar parts.

Stock ignition systems and stock carburetors work very well on modified engines and it is generally a waste of money to replace these things until engine cubic inches and rpm's go really high. These should be the LAST things that should be replaced when an average boater starts to modify his engine for more power.

It seems like these forums are full of people who actually believe that MSD ignition systems and Holley double pumper carbs are the first thing to install when modifying an engine. Unfortunately they do not increase performance at all (and generally hurt reliability).

I hope that people reading this appreciate my honesty.

Sincerely
Dennis Moore
[email protected]

If you're going to continue to come on here and spew your tired one sided rhetoric maybe you should buck up and pay to become a member. If you've got time between writing articles about the dangers of global warming to popular hotrodding.. You're a clown.

:lolhit: Perfect :lolhit:

Nope, not promoting my business. My business is set up for other niche's in the performance industry. I deal very little publicly (ie: paying customers) with performance boaters.

I agree that stock Merc ignitions are very good for the most part. I'm not an MSD fan for on the water. My favorite ignition set-up was the Merc Voyager (GM external coil Hei's) distributor with Crane Box. Very reliable and the Crane Box had most of Merc's high performance advance curves available with just a twist of the dial.

Crane marine boxes are gone, but another company has emerged with the same type. They even have a computer programmable one.

Actually, what really bothers me is a so called professional engine builder that install heads designed to increase low speed torque and single plane intake manifolds designed for high speeds. It is just this type of crazy engine combinations that make the good engine builders in the marine industry look foolish.

Have you tested same sort of build both ways ? Vic Jr vs RPM dual plane ?

On a 502 ?

Not an OEM iron head, not a low lift HR or Hyd ?

Meaning a Modern effecient cyl head with modern higher lift HR ?
Edit in: You mention in your BBC Marine book the Crane 731 and 741 more than once....how about with these cams ?

I think you may change some of your answers if you did.

IMHO and experience.

I'm just gonna save this one in case it disappears..

I will admit that with the slow economy and the boating business all but dead, I am on this forum to help promote my business (as are you).
I

I hope that people reading this appreciate my honesty.

Sincerely
Dennis Moore
[email protected][/QUOTE]

Dennis, YOU ARE A AZZ CLOWN!!! Hey, why don't you sell a few more copy's of your outdated book and use the money to become a PAID member or better yet, being that you are going to "promote your business" on here:eek:, why don't you spend the 500$ and become a PAID advertiser!!! As far as "holley carb's having the needle and seats dry out over winter" about 25 years ago they came up with MODERN materials to make needles and seats from that seem to last YEARS AND YEARS, I have pulled holleys of the shelf that I built 15 years ago with quality float bowl gaskets/ metering block gaskets, blown them off and put them on a motor without having any leaks. I think the last time a boat came with a quadrajet was what, 1989? This is 2011 DUMBFUK, why don't you tell some oso'ers about this modern invention called "fuel injection" or didn't you learn about that back in quadrajet school, you are good entertainment, you remind me of the old timers that were convinced they needed to rip all that modern hei stuff and efi off motors and bolt in points distributors because god forbid this modern stuff is just to complicated , Smitty

Spend 80$ on parts and just fix yours, cheapest way out, simple to tune and I assume it is already tuned correctly for your motor, why start over? Smitty

You guys are a real class act.

50% of the population of the world responds with emotional reactions to problems that frustrate them.

They are called women!

I can't think of a better thing to respond with other than YOU men react like women!

HA HA HA

You should be real proud of yourselves.

It would be nice if you ladies could keep it on technical topics and not get personal.

Dennis Moore

You need to meet my wife then. :eek:

One of our fist dates involved going thru a set of Dom's for a twin engine SC boat. Me with one, her with the other.

If your lucky she might show you how to go thru it instead of throwing it at you. She might....dunno...can't be responsible for the actions.

Holley's (including Dominators no less) and women. Both a great part of my boating life. You figure ? Guess you don't !

I guess it's guys, Edelbrock carbs, and stock-mild performance motors for you ????????????

BTW: good luck with the global warming crying you've been speaking/typing but while still promoting 'performance' boats.

WOW, all of this from a question on a Carb ?

I do enjoy the knowledge I get from you guys weather it is opionion or fact.

Good Points Made?
 

I think Dennis has made some good points in this quote. For those with different opinions, please debate each of his points made. I think this is a great debate. Making personal attacks is not making a good argument. For all the novice boaters out there, including me, this is one of the most asked questions regarding carbs.

THX

What are your opinions?
 

I do not know for sure if Dennis is correct, but his points make sense.

Instead of claiming he is biased, what are your arguments against his technical claims?

This goes to all the Pros out there.

OP says he has an HP500 clone. Which would you have feeding it ? Quadrajet 750, Edelbrock/Weber 750 / or Holley 850 as OP has ?

DM makes suggestions, as he stated, for those doing bolt on's like intake/carb on stock motors. His more modified engines include slight cam upgrades and exhaust. Maybe larger valves in factory heads.

That's it for his engine mods.

#2: He says Holley's are junk and for some reason he doesn't think Mercruiser uses them. #3: Volvo Penta uses/used Holley 2bbl's and 4bbl's pretty much for ever.

Maybe we should distinguish the terminology between performance and high performance ? Although, even with mild performance, many of us can get superb driveability, mileage, and better top end with a Holley.

Ask every hi performance marine engine builder out there what they use for carbs:
Mercury Racing
Sterling
Keith Eickert
Zul
Chief
Teague
Crockett
M.E.R
Pfaff
on and on and on and on.
Or should I continue ?

===============================

As far as the carb tuner statement against Prosystems, Willy's, Nickerson, Williams, etc,etc is another totally ubsurb statement.

Just like with Holley's If one can't tune or modify an Edelbrock/Weber/Quadrajet for ultimate idle, driveability, and performance for their particular engine what do you do ? You send them out to or buy one from someone that can.

Mild performance out of the box calibrated carburetors are made for specific size mild performance engines. Mild performance. An out of the box Qaudrajet / Edelbrock 600/750 / Holley 600-750 are all calibrated for mild performance. 600's for small blocks, 750's for 454's.........................This concept is easy.

No reason for anyone to hate any carb. They work out of the box great for what they are made for. They don't work well for what they are not made for.

If someone doesn't understand how to work on a certain carb that does not make it junk.

If someone choses the wrong size or calibration carb, this does not make it junk.


We are in the 2010's. No longer 1980's. Things have changed a lot. Even with carburetors.



.