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Discussion Starter · #1 ·
potential dumb question but how/why are some of the new brawler/holley 4150 series carbs sold without a metering block? They have rear jets threading into a plate and changeable air bleeds.

I was given a 650 brawler and have never touched on before.

Is there an advantage or is this a cost saving for Holley?

Chris
 

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Those with the small plate are actually designated 4160, and not 4150.
It is just a cost saving measure, now that there is a jettable thin plate made there is no difference in function.

In the past there wasn't a jettable thin plate, it was just fixed orifice, so if you wanted to change the rear jets you had to buy a different numbered plate.

Holley has been using this idea for 40+ years, it works just fine.
 

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You have a 4160 not a 4150, these use a metering plate with no separate jets but metering drilling the plate is stamped with its rated equivalent jet size. There are different sizes of metering plates available. The metering plate can be replaced with secondary a metering block which also gets in to replacing the rear bowl screws with the type front length longer screws and a 4150 longer fuel transfer tube. See the link.



Bogie
 

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What 650 Brawler do you have? Did it come with center hung fuel bowls or side hung fuel bowls? If you want a secondary metering block, there is a carb shop that sells a secondary metering block kit that allows you to run a secondary metering block for way cheaper then what Holley sells it for.

The thing I hate about the rear metering plate that takes jets is if you have a side hung float style fuel bowl you have to have a part of the float cut away then notched and then glue epoxy put over where it was cut but over time the fuel eats away at the epoxy and the float begins to soak up fuel. Also when its a 4160 style and you have center hung floats you have to use nitrophyl floats which are ok but they are shorter so as to clear the rear jets in the plate.

Brass floats go further out and you can use them on the rear of a 4160 using center hung fuel bowls as they will not clear the jets.If you use a metering block then you can use brass floats if you wish instead of a nitrophyl float as some prefer them over the other but its not something you have to do though. Just sharing that information so you know.

That is why you see some Holley carbs with the center hung bowls have a brass float up front and a nitrophyl in the rear if its a 4160 model.

I have a Quick fuel 600 Slayer which has the same setup as a 4160 style and I just remove the plate and get a metering block for the rear so I can use a 4150 fuel rail to hook up to my carb. There is a lot more options for hookup with a 4150 then a 4160 if there center hung fuel bowls. The side hung fuel bowls it does not matter since they only have one main fuel inlet. Nothing wrong with the plate style with jets but I prefer the metering block over it.

Don't know what engine you have or the specs but you can also make your Brawler a 4 corner idle setup as well with adding a secondary metering block with screws and just changing out your secondary idle air bleeds. Hopefully your carb is in good shape as lately Holley seems to be really horrible on quality control with a lot of there carbs.
 

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Discussion Starter · #6 ·
What 650 Brawler do you have? Did it come with center hung fuel bowls or side hung fuel bowls? If you want a secondary metering block, there is a carb shop that sells a secondary metering block kit that allows you to run a secondary metering block for way cheaper then what Holley sells it for.

The thing I hate about the rear metering plate that takes jets is if you have a side hung float style fuel bowl you have to have a part of the float cut away then notched and then glue epoxy put over where it was cut but over time the fuel eats away at the epoxy and the float begins to soak up fuel. Also when its a 4160 style and you have center hung floats you have to use nitrophyl floats which are ok but they are shorter so as to clear the rear jets in the plate.

Brass floats go further out and you can use them on the rear of a 4160 using center hung fuel bowls as they will not clear the jets.If you use a metering block then you can use brass floats if you wish instead of a nitrophyl float as some prefer them over the other but its not something you have to do though. Just sharing that information so you know.

That is why you see some Holley carbs with the center hung bowls have a brass float up front and a nitrophyl in the rear if its a 4160 model.

I have a Quick fuel 600 Slayer which has the same setup as a 4160 style and I just remove the plate and get a metering block for the rear so I can use a 4150 fuel rail to hook up to my carb. There is a lot more options for hookup with a 4150 then a 4160 if there center hung fuel bowls. The side hung fuel bowls it does not matter since they only have one main fuel inlet. Nothing wrong with the plate style with jets but I prefer the metering block over it.

Don't know what engine you have or the specs but you can also make your Brawler a 4 corner idle setup as well with adding a secondary metering block with screws and just changing out your secondary idle air bleeds. Hopefully your carb is in good shape as lately Holley seems to be really horrible on quality control with a lot of there carbs.
Thanks for the replies.

It is a dual feed center hung. Holley wants ~50$ for the feed line with a 5/8 inverted flare inlet. (8.8" OC) I have to make a quick 90 turn to clear on board air system.
I have a a feed line for the 4150 with metering bock but obviously it is too long.

I guess I will use it on something.
 

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I don't know what your engine specs are but if you go to allcarbs.com and check out the link below, they have a secondary metering block you can put on your carb and it has all the stuff you need to put it on without needing to buy anything. All you have to do is put your jets on and your good to go. You won't use the transfer tube though as its for side hung fuel bowls and since you have center hung bowls you won't need it. I use that metering block for all my Holley carbs that are vacuum secondary. It will change the idle calibration on your carb as it comes with a .031 idle feed restrictor size and I have not checked in a while but the rear metering plate on the Quick Fuel brawler carb used to come with a .039 size restrictor drilled into the metering plate and by putting in the secondary metering block with the smaller idle feed restrictor size it will lean your idle circuit out quite a bit but not so much it can't be tuned depending on what your engine specs are and your camshaft specs.


I don't know if Holley still makes the Quick Fuel brawler carbs made so you can change the idle feed restrictors in the metering block or not on the front. It was normal for when they first came out but I have not came across one in a while.
The block is like $43 bucks before shipping and I get my stuff from them all the time and they have a lot of stuff if you need parts. You can also do a little customizing on the rear block and make it changeable on the restrictor size like the primary block is but you have to drill out the pressed in idle feed restrictors in the metering block and then tap it for 6-32 thread size and then you can buy some brass allen set screws from mcmaster.com and you can buy a cheap drill bit gauge set off of ebay that has like .020 through .039 drill bit sizes and you can then change them out to whatever size you need for your engine if needed but caution has to be given before you do this method as you have to be careful when doing it but the first time I did it I had no problems doing the mod.

 

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If your not using the old 600 that you took off you can use them on your Brawler carb if you want to as they are interchangeable. I have some Holley carbs that I got center hung fuel bowls for but I also have extra side hung bowls left over from some parts lots I have gotten over the years. Also Allcarbs sells side hung bowls brand new as well if you want new bowls.
 
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