Fine Tuning Holley Carburetors For Dual Quad Intakes

[@coopstain6458]

i love this, he basically made every passage on that carb tunable, if theres a hole theres a jet

[@steveadams5190]

Andy is a guru at explaining!!! Makes it very easy to understand. I'd love if you/him could cover dual quad setups for a blower application.

[@williamhowland1031]

Anyone that didn't subscribe to Unity after the last video is not watching this to learn. It is immediately obvious Unity knows what he is talking about. Great job as usual and Thank you, thank you, thank you for introducing us to the Unity channel!!

[@tommyornduff9518]

I have run two 600 1850 be for on the street with 350 no problems but it loading up but now am older am building a 34 ford truck for a rat rod I want something I can drive alot I got some good information thank you Tom from tn.

[@bunter6]

9 dislikes from the Carburettor Magic Circle who don't want their secrets given away for free. 🧙‍♂️

[@pablojanski.2559]

Being a professional carb builder and tuner, IDK how many times I see someone do a carb video that I can't watch because of bad info.. Andy Did a great Job! and as he said, you could go for hours. emulsion setup, air bleed tuning ect ect.. another important factor, that actually should be done first is, Ignition timing.. If that isn;t right first, tuning the carb can be fruitless. Great Job andy! And Thanks for the great content UT.

[@howabouthetruth2157]

Man, THAT is some impressive knowledge. And 16 mpg from a big block, tunnel ram, and duel quads that runs 11's in a truck weighing 3,600+ lbs is nothing short of astounding. ( The EFI guys will be jealous......... I can hear all of their sabre rattling already, lol. )

[@denniswallace8378]

I work at Holley. I started in assembly. Worked into cnc machining metering blocks and now I am maintenance keeping the cncs running. We set ours in kinda the same way. With that said we have full vacuum through out the plant so no need to have running engines. Just for info we sell metering blocks with a range of specs.

[@denniswallace8378]

Holley also sell many parts to our carbs. No need for after market. Go to Holley .com for all your needs.

[@UnityMotorSportsGarage]

That is awesome! Thanks for Watching Andy

[@needmetal3221]

I'm glad you've found some good guys to collaborate with. His vacuum syncing tool is smart.

[@kevmay21]

I tuned my main circuit like this on my 408 stroker with 800DP. put in power valve block off and square jetted until I was running ideal A/F for WOT(12.5ish). That put me at 84s. I then sized the front jet until I got the lean cruise that I wanted (mid 14:1 area). That put me at a 68 main jet. I then sized up the PVCR to resquare the primary side to the 84 size in the back. I don't get his mileage but I am not running vacuum advance and don't have any overdrive. Car runs great. Nice and lean at cruise without cylinder wash and giving up nothing at WOT to get that. This was a great video. Love what he did with the transition slot and idle circuit.

[@kurtzimmerman1637]

andy really knows his stuff when it comes to carbs, induction systems and engine building! that why I always told everyone to watch this guy. he's sharp!

[@InuranusBrokoff]

Hey Tony, was late, but saw the new shop. Things are about to get interesting.

[@edwardsmith6609]

Way above my Pay Grade, I can't even raise chickens or keep house plants alive. But I do appreciate some good plain speak on these matters. Very cool video...I'll pass it along to some buds of mine.

[@edwardsmith6609]

Can I put a 6 pack on my 225 or am I Pissing in the Wind ?

[@elektro3000]

Uncle Tony, my brain's full!

[@pete540Z]

Great stuff! Like Andy, I've seen others go deep into the idle and transition circuits, tuning with custom orifice sizes and get great drivability and fuel mileage from a holley. Some of the higher-end Holley and Holley-style parts come with those circuits tunable with small jets. One point of clarification. When Andy is saying "Drill and tap for six thirty-second" or "eight thirty-second" he doesn't mean 6/32" or 8/32" but #6-32 or #8-32. That is, #6 diameter, 32 threads per inch, or #8, 32 threads per inch.

[@ericdeyarmin2469]

8 barrels, 8 cylinders equals all the fun! With a pick of a dual carb setup. That would be a awesome shirt

[@davidstuck2866]

I like Andy, he reminds me of myself when I was young working on motorcycles. I doubled the power, and the miles per gallon on my Kawasaki 2 stroke triple. It took a while, mostly because I had to learn the tuning part by trial and error. but when I was done, I had a great bike.

[@tomnekuda3818]

I used a tool just like that to synch 42DCOE Webers on a Chevy Cross-Ram manifold. Works great/gets instant response/great power and economy. I've used the little wires forever on Holleys to balance and get air/fuel ratio. 660 double squirters were excellent carbs....hard to find today.

[@MrTheHillfolk]

Uni-sin I think they were called. There was another one too, but I forgot the brand name. And one was better then the other.

[@tomnekuda3818]

@@MrTheHillfolk Mine was a Uni-Syn and there was a learning curve to get to know just how to use them. I would use a length of hose in the throat of the carb at idle with the other end to my ear to get them close...they would sound the same right in the throat....then I'd put in the Uni-syn to get them "perfect".

[@cobrajet8866]

Andy Rocks. He is very detailed and has a ton of experience. Both UTG, Unity Motorsports and Thunderhead 289 are the best 3 to learn about Air Fuel Ratio and Carburetor Tuning. AFR is key - watch all three channels.....16 MPG is possible...

[@dartvader9939]

Now i need to find a good used dual quad intake! Great video

[@davenkaren2572]

Is this the same dart Vader from the old Dart heads forum?

[@kenleppek]

That guy has forgotten more than I'll ever know...Holy shit.

[@robertcurrer5318]

Love utg and I have learned a lot from him keep up the good work

[@pri3stburgess168]

Definitely one of the best videos ever for tuning

[@richardturk7162]

Andy brought out a few things I was going to say about smaller jet sizes to use but he said it much better. Great stuff Tony.

[@3Repete]

So glad Andy is out there. He really went to the detail in this explainer. Turns out that the carbs he got to really work had to have idle and low rpm fueling reduced below the available settings the carbs arrived with. He showed where he did the changes and explained the why of it. I am looking into a dual 4 barrel setup and this just made me feel a lot better about it.

[@ianshaw8273]

Thank you Uncle Tony for some refresher on what i already know but cant stop watching becouse i always learn something from each episode

[@bigbear5510]

Thank you Uncle Tony! Thank you Andy for the excellent information!! You sound just like the guy that use to tune my bored & stroked 396 back in the mid 80's. I started off with a 850 then changed over to a dual quad setup w/2 650's, not only did I get better performance gains, I also got better gas millage on the street. I think I was getting about 14 MPG, if I kept my foot out of it!

[@paularndt6111]

That man is a mad genius of carbs🤓

[@SweatyFatGuy]

I think I need to make that vacuum measuring tool. As he is going through that, I am thinking the same things, but not about restricting fuel through certain circuits because of the fuel I use. Makes me wonder if I don't need to do so much work to a carb to get it to run well on E85. Switching fuels changes things, and now I want to find out with my Offy intake and a pair of single feed 500 Holleys. I was wondering how he would address the jets and PV, because that is where the power and cruise economy come from. From my experience he is spot on, and it makes sense running two carbs that you need to back the idle 'air-fuel' down by a lot. I hadn't thought of that, and my engines make lots of vacuum at idle. The one thing I would highly recommend if you want to get into tuning or building carbs (like I have been for E85, but really for any fuel) that you invest in a wideband O2 sensor. I use my 65 GTO and its 455 with 11.5:1 to test carbs I build, it has an O2 bung in both collectors, so I can see how either bank is running, or put the FiTech on it and have the wideband in the other collector to see where the AFR actually is. Unless you can see how its running, you are guessing, and reading plugs is damn near impossible on ethanol, they look perfect and new after hundreds of runs. I can install a bung on another car, then by simply plugging my wideband in with a couple spade connectors and a good ground I can see what its doing at idle, cruise, WOT and everything else. Its very beneficial for pump gas, because your street ride spends a lot more time at part throttle than it does at WOT. I don't run ethanol with gas scale O2s and then convert it, I like to see what its actually doing and mine goes roughly from 11:1 to 7.5:1 AFR. If you like the way a high compression 60s era V8 runs and want to drive it every day, then E85 is the way to go. 13:1 and boost is easy on E85.. and you put the timing where it wants it, not where it doesn't try to rattle the engine to death. Driving a 13:1 455 around making ludicrous bottom end torque is silly grin inducing fun.

[@peggyparrow2059]

My hubby and friend are building a 327 old school style gasser motor with a tr1 y ? Tunnel ram. They swapped the 450s for 600s and are putting down leg boosters in them,and have quick fuel thin plates that have holley jets in them for 4 corner adjustability.

[@MrTheHillfolk]

Now I know who Andys voice reminds me of. Hi,I'm Larry and this is my brother Darryl and my other brother Darryl 😁

[@downandout992]

To my California ears he sounds like pretty much everybody from the area between Arkansas and Ohio.

[@MrTheHillfolk]

@@downandout992 it's not so twangey that you think he married his sister though , thank God.

[@duccanard9079]

Did most if this back in the 70's.On a 71 F250 390 with a RV cam from back then,Mileage maker,I think.Thew a Doug Nash OD behind that hog of a C6.Finally got past 18 MPG after sticking in a DS2 and recurving it.Now for some damn floorboards.

[@jameshuban6515]

A homemade unisyn gauge. We used to use them on my brother's 67 Datsun roadster with SU carbs.

[@roknroy1]

best carb video ever!

[@UnityMotorSportsGarage]

Thank you for that... Andy

[@michaelferro897]

absolutely great stuff!!! I wish I had a car and goodies to mess with to do what he instructs! this would be an awesome segment to keep running once a week or whatever! extra expert tech tips or something like that, definitely a winner!!! thanks again guys!!!!

[@cranerigging3604]

Great video and information Tony and Andy , I also like the " flow meter " tool at 2:35 !

[@davenkaren2572]

I built one from his instruction on his other video- awesome tool for dual quads!!!!

[@testpilot6456]

This recalibration "secret" has worked on any carb I have applied it to ,even original unmolested engines have shown improved economy & drivability with the twerking of their original OEM carbs as tolerances occur in mass production. Qjets,AFB,Thermoquads are really great carbs & were rubbished by the aftermarket to sell their replacement carbs. Even had great results with Japanese ,Italian ,English carbs. I bet Andy has nice clean plugs that don't need cleaning every week.

[@chrisgleis2821]

You would think Holley would have those orifices jetted like Andy has done.Good stuff.It makes alot of sense.

[@kevinjohnson9372]

Some after market blocks are full of jets to tun things all over the place

[@DavidDahm0o]

Awesome video! thanks buddy keep up the good work. Going to share this one to all my friends.

[@UnityMotorSportsGarage]

Thank you! Andy

[@makkepuu]

I have a smog-era Ford 460 that I bored 030 over with flat tops, re-worked the exhaust ports, lunati #06169 cam and headers and it get's 18 mpg. The car is a '76 Ford Thunderbird that weights like 5000 pounds

[@ernestrusucarp8048]

Next level, as promised. You're the man Tony

[@brucekultgen132]

I've been using 2 stage power valve for forty years, mostly on ford autolight carbs. Try to find ford jets 6 to 8 jet sizes smaller ! Had tap ford jets to fit holly jets , and bought Mopar direct connection jet packages 4 at a time,for tunnel rams.

[@cmd2789]

Love the knowledge, thank you

[@chrishensley6745]

Very nice Video man...back in early 90,s ran a 327 small journal 291 heads,tunnel ram with 2 600 holley,s,m-20 muncie,3;55 gear 56 chevy 4-door...done pretty good man...The best was street racing a 73 challenger 360,,direct conn. 292 cam edel. intake 750 holley,headers,pistol grip,3;55 pos Good Mopar dude,black on black and well tuned..mine was too...Show car was the the Mopar and sounded awesome...we started at a 15-20 mph roll and got him by halg a fender length...ran again....got him barely.....ol tunnel ram is hard to beat,I had stock heads,no porting,,,the Mopar dude had alot in the car but dont now on the heads...but I GOT HIM..Back in the early 90,s!!!! High dollar car against a ol 4-door 327 4-speed chevy.....Been a Chevy Lover eversince!

[@chrishensley6745]

This car was a all Direct Connection hot rod parts car and I got him with and ol 4 -Door Chevy car with a Tunnell ram Chevy! with no money working at Auto Zone back in the day........Money can buy you alot though nowandays.

[@doctorromex7804]

Totally awesome, very informative. That's info that will normally cost money right here on this channel for FREE....

[@eaglewolf7637]

Outstanding, keep the carburetor information coming!

[@deesel666ify]

Thankyou very much for the education. I truly appreciate it.

[@normlenhart9565]

I had a freshly built 400 Ford in an F150 on 35s pulling 15 highway.4.56 gears, performer cam and intake W/a 670 Vac secondary and an MSD Digital 6 ignition and billet distributor. I had a lot of people tell me it was impossible and I was full of crap. Oh well. My truck just kept right on doing it and didn't care what the internet 'experts' said it was or wasn't doing. Tuning matters.

[@MoparMan-ff8fb]

I also watched Andy's video Glyptol to coat the inside of the engine block . I knew about Glyptol but he talked about it more indepth. on my edelbrock 600 edelbrock I found out that after fully warmed up I'm suppost to check vaccum pressure and take that number and divide it by 2 . say it's 18 . 18 ÷ 2= 8.5 then I bought the tuning kit and had to use the silver spring instead of the stock metering springs to fine tune it

[@AtZero138]

Way to go UNITY!! AWESOME BROTHER

[@gcaprice406]

My mind is blown. I appreciate you going through the trouble to make this video, Tony and Andy. You’ve earned not getting a snide comment from me for at least a month. Can’t wait to jump on his channel as well.

[@markstopkey4085]

Great information

[@ccarter2184]

This guy is genius

[@livewire2759]

This is basic carburetor engineering. I learned about all of this in college, and I can say he's absolutely 100% correct on everything he said. More people should know this. I'm always telling people that 4bbl carbs are more efficient than 2bbl carbs, and that I get nearly 20 mpg with my old chevy truck with a 350 and quadrajet and nobody ever believes me... but this is how. Tuning is so much more than just replacing jets.

[@WiSeNhEiMeR-1369]

HOWdy U-T-G, ... & ANDY, ... Thanks COOP the WiSeNhEiMeR from Richmond, INDIANA ...

[@troyberg65]

Awesome videos; for another part some info on linkages and side mounting compared to inline mounting and the tuning changes they may entail would be very interesting.

[@6ford9]

I have the same carb sinc got it from a old school tuner that passed away love old school stuff

[@5000rgb]

Thumbnail is perfect.

[@1962pjb]

It would be interesting to learn about his views regarding carb tuning with a wide band O2 sensor.

[@UnityMotorSportsGarage]

I have a dual wideband in CASPER you can see it in my 600hp and 16mpg video... When you have a wide band you can really see how each circuit interacts with each other... It's a true eye opener! Andy

[@1962pjb]

@@UnityMotorSportsGarage Thanks! I'll check it out. I'm assuming the values have your blessings? 😊

[@UnityMotorSportsGarage]

@@1962pjb I have to say it is pretty cool to see, because you can see in real time when each circuit comes in.... like in my case Im running almost 15:1 at idle and then you would just crack the throttle and it would go to 11:1 give it more throttle to get into the main circuit then it would go back to 14:1... You figure out that something is up with the transfer slot circuit real quick.. you would never know that otherwise...

[@6426yy]

@@UnityMotorSportsGarage Do you have a video on power valve tuning?

[@ludditeneaderthal]

That sync tool is actually a modified version of the rig used to "balance" those old brit twin SU setups, basically just adapting the single bore flange to a "tophat" for a holly flange. His self fabbed jet system (idle, transfers, power valve orifice) converts the "restricted puking" of the stock Holly to the "infinitely tunable" engineering of high end Mikuni bike carbs, so much so that the "Mikuni tuning manual" would give a great leg up to the bonehead trying to reproduce his results. His "solution" is actually "no new ground", yet pretty damned ingenius in practicality and repeatability of results, as well as making those Holly squirt bottles an efficiently tunable PRECISE metering system. The mods and an assortment of his setscrew jets for each circuit would allow EXACT tuning for any variable (temp, humidity, altitude, etc) or set of variables. Holly should pay attention to this vid, and offer his mods and jets as a stock setup, it's honestly that practical, usable, and worthwhile. BRILLIANT! is the only comment that does him justice for this

[@Geoduck.]

I've always thought one four barrel is best for street. These two videos are very informative. Back in the mid 70's my buddy had a tunnel ram with two Holleys on his built 360. It was a DOG but looked great. My stock 340 magnum smoked him no problem.

[@joeblow2063]

He needed this video haha

[@caddydaddy6728]

WOW UNK THIS HAS MY HEAD SPINNIN NOTHING BUT GOOD STUFF 👍👍

[@texasmopar5557]

I think these grass roots rot rodder tech videos are bad ass. Uncle Tony could host various guys from expert body men to transmission and diff builders.

[@peggyparrow2059]

My hubby said he filled the holes in the throttle body with jb weld and re drilled them smaller.

[@jontrudell7529]

CARB CULT LEADER ANDY!!! lol

[@UnityMotorSportsGarage]

Don't know about that... But I will take it! Andy

[@herbnalis3723]

I think there is a market out there in the 'man cave' segment were a 'BBQ Tunnel Ram' grill would sell & I could see people investing in a start up company.

[@bubot17]

I'm also a subscriber to his channel, he also has great content

[@bluecollarcook]

Thanks.

[@dennisyoung4631]

Sounds like a Uni-Syn… There are such things as *Brass* Allen set-screws. I bought some for the bike stand.

[@moparcasey3135]

Good stuff!! I want more!!

[@jessebrandt452]

Please, let's see this same video applied to edelbrock / Carter AFB carbs!! Great content, keep it coming.

[@everetmauiman5321]

Love all your videos uncle TONY your a very awesome you tube your videos is very awesome on point and you go straight too the point i love it keep on coming with your videos

[@campervanbug7658]

We can watch for hours👍

[@forthwithtx5852]

If Andy isn’t selling custom jets and tapped/threaded Holley parts, he’s missing a business opportunity.

[@bluecollarcook]

🤑 Nothing is off the table.

[@chrislore2681]

I made one of those tools to sync to Carter AFB he's on a 1970 Hemi Cuda

[@NebukedNezzer]

great Andy Wood teaching video.

[@davidlandeck9566]

Thanks for all the info

[@jontrudell7529]

CULT LEADER UTG !!!

[@garymatthys3605]

Andy hangs around with David Vizard. Just sayin'. David's one the smartest guys in the business.

[@UnityMotorSportsGarage]

Yes he is... He has forgotten more than I will ever know! We have been friends for years and he has taught me so much over the years! Andy

[@Russeljfinch]

You’re right UT we need one for the carter 👌

[@seanfagan6998]

Hey Tony here in jersey we are going through a auto retro thingy. Front page news people just can't seem to keep their cats on their cars. They are stealing them like hubcaps in the 70s. I remember them doing it 20 years ago I guess precious metals must be skyrocketing. Have the cost of cats followed.

[@yeboscrebo4451]

Thanks tony, thanks Andy

[@nhra7110]

Outstanding videos from Andy!

[@werewally3156]

Hells yes.

[@waynep343]

Lets talk about idle transition.. from idle to around 1,800 or 1,900 RPM.. must use a mirror and a flash light or even a timing light aimed down the primary bore while slowing increasing the rpm till you see the fuel start to trickle from the primary boosters.. look at the tachometer and note the rpm,.. then use an RPM slightly below that.. so all the fuel is coming thru the idle feed restriction.. now.. look at your air fuel ratio display.. i set up mine with the gauge mount on a piece of carpet so i can rest it on the dashboard without doing a hard install.. where is your air fuel ratio at this engine speed .. rich or lean. if its rich.. go smaller on the idle feed restrictions.. if its lean.. go bigger on the idle feed restrictions.. the idle feed restriction/low speed circuit tapers off as the primary circuit starts to feed fuel thru the booster venturi's this happens up around 2,400 rpm when the idle feed restrictions almost stop feeding.. you need to bring the RPMS up to the point where the secondaries are almost ready to open. look at your air fuel ratio.. is it lean or rich.. if its lean.. increase primary jet size... if its rich decrease primary jet size.. getting it to idle.. i hate drilling the throttle blades.. but i have used fine thread needle valves to allow air in bypassing the carb.. . some performance carbs.. demons have it on a few models.. have a center idle air bypass screw down the hole where the air cleaner stud is threaded in.. this is mounted in the base plate.. and prevents the need to drill the throttle blades to get it to idle.

[@mikeb8811]

AWESOME VIDEO. Lots of good stuff ‼️👍🏻

[@jamest.5001]

Great video, reminds me of the stuff I forgot, and stuff I was unsure of! I love a Holley , I'd most likely never buy anything else! It is the only carb I have bought new! Unless it's for a small engine, I have even thought about putting one on a motorcycle! Ha...

[@alyssaway94]

Try too get a 440 6 pack on nitrous injection on each port of intake in Bristol Tennessee Moter Speedway in high altitude!

[@josephmclovin9763]

best thumb nail ever

[@gavindowell8239]

Great content. Love your work UTG

[@karlsracing8422]

Larry Sheppard has a video on this with a cross ram big block mopar.

[@bobwhite4344]

great info.

[@jimifed2798]

I understood most of it but the part about drilling out the angled holes in the power valve chamber and then restricting it with a smaller orifice then what was there to begin with. I thought the idea was to get the PV to flow more so u don't go up main jet sizes. Unless were restricting vaccuum? Not fuel.

[@direct998]

Got a tunnel ram on my 440 mopar . was running an 850 double pumper . followed your advice and picked up 2 750 double pumpers . proform 750 annular main bodies and throttle plates . all metering blocks the same . 1:1 CARB linkage ( sideways mount ) . initial timing 22 . total 36 . any more advice ? Will come back and keep you posted .

[@yeboscrebo4451]

Yes, please cover the edelbrock

[@edge2sword186]

Can you do one on the shaft bushing replacement because many people don't even know that they will melt if left in Hydro seal for too long . I like that as much as replacing Cam bearings . Ha Ha !

[@davenkaren2572]

So, what might be a good “starting point” for jetting and power valves on a bigger engine- 496 stroker, Weiand TR, 2’ spacers to clear linkages, full roller 640/ 640 lift 296/ 308 duration 114cl, 10.5:1, forged bottom, two 750 Brawler 4150 dp’s, MSD ignition with digital 6al box in a jet boat? My carbs I ordered from Holley were the race brawlers with no chokes, down leg boosters, primary jets 74, secondary jets 84, 70/ 70 air bleeds, and 4.5 power valve…………… in your professional opinion, where do you think my jets and power valves should be? Is this pretty close for a dual quad tr starting point? Or am I needing to change a few things? THANK YOU SO MUCH IN ADVANCE, SIR!!!!!!

[@jeremybodell3619]

Does adding jets to tune the power valve serve the same purpose as changing air bleed size? The carb in the video probably doesn’t have adjustable air bleeds but you do see it on some models . Are they trying to achieve the same thing but just going about it a different way?

[@WaybackTECH]

His knowledge is something you won't get at Wyotech or Power Nation. Some of that does apply to single carbs with power valve and jet size and plenum size. Good stuff. Complicated but good.

[@jasonhooey5677]

I would love to hear one that applies to the edelbrock avs2 carbs

[@UnityMotorSportsGarage]

I'm going to work on a video on the Edelbrock/Carter carbs.. when I get some time.. Andy

[@duncandmcgrath6290]

Solid info 👍thx guys

[@Bad-decisions-and-good-times]

I think its silly when people say big blocks cant get decent mpg. My cammed mild 750cfm bbf gets 16

[@ericburns6947]

to Uncle Tony I love all your projects especially bottle rocket and the daily driver we must hook up someday we must test each other I'm from Chicago hey I don't mind coming down to Tennessee to race you just in a friendly competition in a friendly race I'll see you soon