I have a holley 5200 that I plan on putting to some use sometime in the very near future just have a few questions regarding it if anyone knows

the floats on them from my understanding are the foam covered plastic ones and they tend to leak from what I hear. would it be fairly easy to replace them with the brass ones or am I going to run into more trouble doing that instead?

with the jetting of the carb how does it all work? I'm not sure how these things work without needles in them. I'm used to something like a quadrajet that has the jets and needles in them so how do these things work with the emulsion tubes, air bleeds, and fuel jets instead?

when tuning the car how do you know if you need to change the fuel jet vs changing an emulsion tube vs changing air bleed jet? this way when tuning it I'm not changing an air bleed when instead I should be changing an emulsion tube.


and are there any other problems with this carb I should worry about or what?


oh one last thing I noticed the venturi area is chocked down quite a bit compared to some of the other carbs of the same make that were made a little earlier is there anyway to open them up to let more air in or as I assume prolly bringing myself more trouble then anything by trying to do this

First off I have a 4150 model holley, but I'll try my best to answer some questions:

The floats shouldn't be a problem, I have the brass ones and they haven't given me a problem.

When jetting the carb, you start with the primary side. Not sure how much you know about it so I go from the beginning. You have to remove the fuel bowls and you should see the jets at the bottom of the metering body. I use holley's jet removing tool but a screw driver will work, just have to be careful. All the jets have their size stamped on the side, best if you buy a jet kit for your holley. Kit I have ranges from 64 to 99 and wasn't too much if I remember right. As for telling what to do is reading your plugs. Check plug color after a cruise down the highway, try not to jump on it, its only a cruise. If you mash it then you'll be testing the accelerator circuit and not the main jet circuit. When you get the plugs a good color then jet the secondaries. Best to jet this by mph on the quarter.

Didn't know you could change out the emulsion tubes, as for the air bleed jet I thought that only changed your idle mixture.


You can get a venturi kit and change them out, as for doing anything to them I wouldn't because you'll change the signal characteristics of your carb. It may get more sluggish, its best to do that if you can have it flow tested.

Hope all that helps out good luck

Building a dirt track riding mower, are we?


You actually have a use for one of these, or are we installing several?

If there is any chance that the engine may get exposure to methanol, I would avoid using brass floats. Ethanol is not a problem, but methanol has a real affinity for lead, which may or may not be a component of the solder used to join the float halves, but is certainly an element found in the brass used to make the floats.

that looks like the piece

and if your trying to claim that is going on my mazda there is no way in hell. unless I install multiple units but as it sits right now the EFI works much better then UI think that would.

I do have something I can use one on though though I found out the one I grabbed isn't the greatest flowing on. came from a 79 fairmont and it seems to only flow 220cfm vs some of the ones from the earlier pintos that flow 280cfm
and I'm too cheap to buy the true weber version so guess I will stay with this one.

though vader I must ask you what is part #33 and #42 of? since I have no idea here.
and no this car isn't going to see alchy so would brass be better or would the foam/plastic floats work better?

and how would one of these work on an iron duke?

last question though is how do you tune one knowing which componet to change?

Well, it says "Holley" on it, so it is very likely that it is a "piece"...

I'm thinking your Mazda would probably try to suck one of those right through the inlets. Whay take a giant leap backward from injection if your's is already running?

I'm thinking that the die castings are the same, and only some machining is different, but unfortunately that may also include the throttle bores. You can probably still improve what you have.

A WAG would be a power piston/valve assembly.

Either would be fine. The later plastic foam floats use materials that resist a variety of fuels and additives.

I could be mistaken, but I believe they were used on Iron Dukes in several '70s and '80s GM vehicles, like Grand Ams, Skylarks, Monzas, etc.

Dude? It's a carburetor! If you insist on using it, simply modify the metering circuits for the application. I'm not sure if jets are commonly available, but since it's a Holley, there's a reasonable chance. Power valves can be altered in the port areas, and the springs can be "calibrated" to alter the fuel delivery. Idle circuits are generally sized adequately for a large range of engines and needs, so that's probably only an adjustment. I'd be more concerned with the transition, pump volume, and enrichment through the power valve and circuits. The secondary is probably going to need very little tuning except for more fuel.

This may help:
http://www.surpluselectron.com/aaron/holley.htm

throttle bores should be the same based upon webers design of 32/36mm units as far as how to improve flow without harming anything I wouldn't have a clue.
but it will be a while till I can get it on a car being NOBODY has an adaptor for it found that out yesterday.
but yes I insist on using it though not for my mazda. the stock EFI is doing good enough for now and if I was ever to go carb on the mazda a holley 600cfm would be my choice being that seems about the easiest swap right now, but no EFI is where I stay

Is this going on an Iron Duke TBI intake? One of those that replaces the TBI300 or 700? Those are a bit of a strange pattern, but I'll bet an adapter can be had. Need a CAD drawing?