Carburetor Billet Metering Block

[Ernest]

Has anyone ever used one on their carbureted engine along with or without an AFR guage?

I plan on hooking up an AEM WB02 guage soon, i would like more tuning capability with my Holley SA770 carburetor to keep my ZZ4 in tune with what the engine wants, for now im going by feel during acceleration and cruising speed along with reading the spark plugs for now, but i know thats no exactly acurrate with todays ethenal based fuels.

Example: Proform 67166C

 

[565bbchevy]

Has anyone ever used one on their carbureted engine along with or without an AFR guage?

I have an AEM AFR gauge on my Monte and have tuned both my Quickfuel 1150 and my Holley Gen 3 1250 with it and both of these carbs have fully adjustable billet metering blocks, the only thing on the metering blocks I have ever had to change were the jets, I find having adjustable air bleeds on both of my carbs were more helpfull in fine tuning especially for the idle circuit and have changed those but never had to get into the circuits in the metering blocks to get a good tune and also consider this a 565 BBC that is street driven.

 

[Ernest]

I've seen the QuickFuel 750 cfm street caburetors that offer adjustabilty of I-AB/HS-AB, front and rear in the main body, adjustable emulsion/IFR and PVCR in the billet metering blocks, and pricy of course.

Not much of a selection when it comes to being a vacuum secondary that has a rear metering block unless its a double pumper, dont want that and im not fond of the available vacuum ports because of the billet base plate, no provision for a seperate PCV valve in the front like i want unless i "T" off the rear one thats mainly used with power brakes, which is a big no no.

Besides, im not buying multiple carburetors trying to figure what im doing, its a waste of money, figure the billet metering block is enough, or i could just drill and tap my SA770 for everything(main body/metering block), but i hate to ruin totally it by accident.

 

[bracketchev1221]

I have to agree with the above on the billet plates. I had them from cfm performance carburetors and they were perfect. I think more than tuning it’s better to get a set calibrated to your setup than buying a cheap set and trying to play with them yourself. My 1150 was run on my 548 and my 565 and I never even changed the jets from the day I bought it. I ran it for 7 years on my engines without a change and many dyno pulls and track passes. It was just that good.

 

[Ernest]

I have an AEM AFR gauge on my Monte and have tuned both my Quickfuel 1150 and my Holley Gen 3 1250 with it and both of these carbs have fully adjustable billet metering blocks, the only thing on the metering blocks I have ever had to change were the jets, I find having adjustable air bleeds on both of my carbs were more helpfull in fine tuning especially for the idle circuit and have changed those but never had to get into the circuits in the metering blocks to get a good tune and also consider this a 565 BBC that is street driven.

Perhaps it'll be more benficial if i just went with an adjustable I-AB/HS-AB main body.

I've seen a few YT videos on general carb tuning, well, especially those with adjustable everything, and came across some saying that they really havent had to touch the billet metering block restrictor jets, just the main jets, only adjusting the I-AB/HS-AB in the main body seemed to have worked for them just like it has for you.

I do have a pin gauge set(.011 to .060) and checked all the factory set SA770 metering block restrictor holes, nothing modified... primary side only details, anti syphoning(.028) / 4 hole emulsion, 2 per side(.028) / PVCR(.060) / IFR(.033) / main body IAB(.060+), probably closer to .070 and HSAB(.025), i do realize the WB02 will have the final say on whats needs to be adjusted, but this is what im currently working with.

Before going with the billet metering block, i'd like to go with this main body, but it doesnt have a timed vacuum port... Be a lot cooler if it did, alright alright alright.

Proform 67101C - https://www.proformparts.com/produc...th-holley-750-cfm-vacuum-secondary-model-carb

 

[565bbchevy]

Before going with the billet metering block, I'd like to go with this main body, but it doesn't have a timed vacuum port... Be a lot cooler if it did.

IMO the adjustable air bleeds will do the job and are easily tuned and very easy to change out especially compared to pulling a metering block off a fuel filled carb to make an adjustment, make sure you get a few extra sets of air bleeds if you go this route,
I would get sets of air bleeds that are over and under from what comes in the Proform main body and also either some blank air bleeds or ones with very small holes that you can drill out on your own to fine tune them.

 

[565bbchevy]

I don't know how much it matters to you but aren't you losing an electric choke going with this main body

 

[Ernest]

Sounds good... i look forward to upgrading the main body and will definately buy extra air bleeds and going that route first, then i'll be going after the holley brand front and rear(vacsec) fuel bowls as well that have an actual sight glass, my holley SA770 that came with my malibu is an older model that use the removable metal sight plugs and gasket.

Yes, the electric choke will be lost, but thats ok.... i'll just have to get used to it, i started off with a holley 3310-2 w/manual choke back in the mid90s, i never hooked a cable up to it to set it manually from the front seat when the engine was cold or even from under the hood, i always left it open.