Inliners International Forums General Discussion Hi Performance 4-barrel carb setup - 235 6-cylinder Model 150 Chevy

Greetings!

I am ashamed to say that I have been away from Inliners since 2002. And since that time I have waffled back and forth regarding changing my single barrel carb setup to a 4 barrel setup. I have finally decided to pursue the 4 barrel route. What type of linkage do I need and who can I get it from if I want to use a 390 cfm, electric choke Holley carb?

At this point I have purchased a set of Fenton headers and the associated gaskets. I also plan to purchase the Clifford intake (with heat).

I actually have a functional 2-barrel carb (with linkage attached) in the garage that was on my chevy at one point. However I never changed the intake or the exhaust to complement the carb and obtain the full benefit from it. My car would darn near choke out when going up a hill with that setup. So I removed it.

Anyway, I figure at this point if I am going to go with the headers, clifford intake, and dual exhaust that I might as well go all out with the 4-barrel route instead of the 2-barrel. But of course, the linkage is the question.

I am welcome to any suggestions.

Eddie Lane
elane352@yahoo.com

You did not specify what size engine you have. I have a 1964 Nova, 3 speed, 194 that is 0.030" over, w/ heated clifford, headers, 2.5" exhaust w/flowmaster, high lift cam and the 390 holley. I am still playing with power valves. I have a slight bog when excellerating, especially on a hill (load) and am trying to balance low end and hi end fuel burn. I have great pix of my set-up...let me know if you are interested.

OOOOPs...just saw that you did post your engine size. Bowie eh...used to live in Laurel...now in Tracy, CA

Eddie
Maybe some of your problems were the 2b on the one bl intake. it may have been trying to Over load the intake?? and this being your bog issue?

6T4Duce
Not knowing your whole set-up Some of your tuning issues may very well be the clifford intake even though it is heated ,It is designed for Mid to top
end power. Where as a Offey is more for Low to Mid range.
Many have seem to have had tuning problems with
Useing the 390cfm holleys.

And seeing that you have a clifford mounted to
a 194 which is the smallest, the combo of intake(mainly) carb. This intake to me personaly is To
much for a daily driver on a 194. carb wise that
should be fine.
BUT my 1 biggest Question is if you have a spacer
under the carb HOW thick is it? Is it a Open
Plate or a 4hole plate?
A full open plate will hurt your Lowend Espacily
on the clifford Because again You have made the
Intake More for TOP end.Again Not knowing much
about the cam You have(you say a High lift?) this
to ?? with the combo Could be to much for the 194
On the low end side of things.??
Still thinking but have a brain burp so i may get
more on this once brain clears LOL.

Okay; I follow you. I was thinking along that line also. So that OEM intake likely needed to be replaced with something that could compliment the carb. I felt that way all along.

Eddie

I ran a 4 barrel on my old 194 Nova some years back really woke up that little car. Don't have info on the carb was one loaned to me from a friends carb collection. This was using the OFFY intake bolted to the stock exhaust manifold.
Cable Lokar type throttle would probably be the way to go.

My friend runs an Edelbrock right out of the box on a Clifford intake, runs super on his 235.

Jim,

Thanks for the response. This does help. The more research I do, the more it seems that the Offy is a better choice to make for a street driver.

If I go with the 4-barrel and the cable lokar type throttle, I wonder how easily can I mate up to my linkage on the 3-speed chevy car. I would have to do some research on that.

But if I go with the OFFY and the 2-barrel carb I have now in the garage, I would have no linkage problem since I already have what I need linkage-wise. I actually had that carb on my OEM intake previously.

I must admit, I do prefer that 4-barrel option.
I bet that you had an automatic Nova and was able to run your throttle cable back to the tranny.

Eddie

MY two cents on 4V Holleys(my preferred carb)is that they need more modification to be right than people want to do,or pay for. Something to consider when running a Holley on a big intake, is the booster signal, a short anular booster will pull twice the vacuum of the straight leg with the SAME air flow, the signal that pulls fuel through the booster depends on the air VELOCITY in the venturi. The Offy will work better than the Clifford with a 'out of the box' carb because of air velocity. But the stock Holley straight leg booster is the absolute worst with a the big Clifford on the street. The sheer size of the Clifford gives it low air velocity on the low end. The wrong way to fix this is to tune every circuit so super rich that that when the main(booster) circuit finally does comes in, it's flows more like a spigot than a finely atomized mist, so then we have to heat the intake to get it to run decent.

Have you ever wondered how a 1000 cfm carb sitting on a tiny 350 Vthing with a huge cam could be easily street driven? and how it had the throttle response? It is because they have 4 idle circuts 3 transition circuits and very sensitve boosters, in other words they dont have good air velocity they have a very specific responsive finely tuned carb instead. Another Holley tuning issue is using jets to tune WOT, it is much more simple to get your jets right for cruise, and do your WOT tuning in the power valve resrtiction channel. In my opinion you can run your Holley just as fine on the Clifford as the Offy, if you want spend the time and money, but by the time you spend the money, and start to really understand how Holleys work, you will (like me) probably wish you had a few Webber side-drafts.

Why not trying an 525-cfm Road Demon?

It sports the anular Boosters on primary and is recomended in the 260 to 400 cid range.
(It may sound a bit big for an 235 but with the right secondary spring it should work)

Plus it has some goodies like bowl windows, easy exchangable secondary springs and adjustable float from the outside.

I have such an Road Demon sitting here plus a Clifford 4 barrel intake that will go on the 261 soon.

I let you guys know how it runs.

Plan B is trying out a variable venturi carb like the Predator. No jetting at all. The vacuum signal does it all.

Frank

Oh, one more thing Eddie, as far as I know there is no Offenhauser 4 barrel intake aviable for the 235. Only for the newer engines. But what do I know.

When do you plan to run it? It sounds like it could work pretty well, what cam are you going to use?, one thing about anular boosters is while they are definately more responsive, they allso like to pull a ton of fuel as the airflow get's higher, thats why tunable air bleeds are nice to have.

I have always wondered how a predator would run on a inline six. I was reading that they come with three fuel curve cams that are set up for larger engines, but they are simple enough that you can easily make your own 'custom' fuel cam.

I have a big project running in my jab that makes me working 14 hrs a day so it may take till mid November to get back on the engine.

The cam is Langdons Bulldog cam.

With fuel prices here in Germnay that are almost twice as high as in the US milage is a big issue.

I fear that the Demon is not an economy carb that´s why I look at the Predator.

Frank

If the predator doesn't work out you might go with some SU carbs, I hear they work great, but they are certainly hard to come by over here. You would need a custom manifold though.

Yeah, SU carbs are the "King Class" but the 41 is my daily driver in the summer, thats why I go for a 4 barrel. I have a LM1 Lamda Meter and 2 wide Band Oxygen sensors to dial in the carb. Works pretty well to tune all the jets and bleeds. It tells you the exact Fuel/Air ratio while you drive.

Expensive but im a gauge nut and I hate guessing when it comes to engine tunig. Most of my friends that tune "by ear" run way to rich :rolleyes:

Frank

There is a Clifford 235 manifold on E-Bay right now going off 11-10 near midnite...Might be what you want...Good Luck

opps 11-04

I again have let too much time pass by without responding here. I need to do a better job.

Anyway I wanted to update you on what I did and where I am now.

Back in January of 2007 I went with the Fenton Headers and a Fenton dual intake. I had two rebuilt Rochester carbs with the short air cleaners installed. My mechanic just indicated that the carbs were not in the best of shape when I purchased them. He stated that the throttle shafts are worn out now and the carbs are really two big for normal driveablity for my 235 engine. He also mentioned that I have float issues. Tom Langdon of Stovebolt voiced similar sentiments.

The car is running. But I would like to make a change. I am seriously thinking about removing the dual carb Fenton intake and replacing it with a single carb intake. Here are my questions/concerns:

1. I like the idea of the Clifford intake since the portion of it that the carb sits on does not protrude as highly up like the one does on my dual carb Fenton. Given that I have the 57 passenger car, I do not have a lot of hood clearance.

2.) I am willing to go with one carb. What makes sense in terms of working on the Clifford and minimized linkage issues?

3.) Will the Clifford intake mate up with the Fenton headers I have on?

I am even toying with the fuel injection kit that Clifford sells. But right now I am not willing to pay that much money.

Any thoughts/ideas? I am open to hearing them. Please get back to me.

If you are after driveability and economy (power too) you should PM Marc (EFI-DIY) about one of his setups, he did a demo at Boneville, everyone that I know that saw it was impressed (I had to leave before it happened ).

Edit:

The two threads here that cover this are

"Bonneville.... TBI Conversion - installation demo"

and

"TBI conversion - installation DVD"

Here in the "High Performance" forum.

Those of us that prefer to stay 'old school' with the 235"/261" the carbs of choice are the potbelly Rochester B's or Zenith singles, check out Pat Smith's article on multiple Rochesters in the 'Tech Tips'section of the website. Clifford intakes that bolt up to exhaust heat are early and very rare.

as they say, just my 2 cents,

Tim

Tim, You could have talked all day and not said "old school". As you know it was my 270 at Wendover that got the efi-dyi treatment. We took off a 500 cfm Edlebrock to put on the GM TBI. And after we were done playing we put the carb back because Marc wouldn't give me the Megasquirt and the 255 lph fuel pump. I got everything else we used and am useing it ( pile 6 ) on my turbo/injection 292 project. Most would not consider any part of this as "old school" Even in an early post to Marc I told him that the future of the 270 included a McCulloch, 2 Zeniths, and an Edmunds manifold. I thought that to be " OS ". Nothing newer here than '57. Now I don't know. What is he point? What is "old school"? Is it a date? A look? A philosophy? I'm growing weary of the widest whites, the flattest metal flake, the longest row of dummy injectors made to look like carbs and disc brakes hidden in phony drums etc. Wayne heads were not "old school" when it mattered. What is a more traditional hot rod approach than a '78 292, '81 Pontiac turbo, '89 GM TBI & wire harness all from the junk yard hooked to a computer board soldered together by the user tuned with a $50 eBay laptop? That my not fit our comfort zone like the SOCAL belly tanker or Moon Eyes but it's exactly what our forerodders were doing. Oh well I'm still going with the McCulloch, Zeniths and Edmunds It's art!

Ok my turn to ask the duh questions.. this fenton dual carb intake what carbs does it use 2 x 1 bbl's monojet?

Beater next year, get your harness and fuel system installed, drive down on the carb, we'll redo the swap for real using your own megasquirt and then you can drive home injected...

If the fenton intake is a 2 x 1 bbl setup, go get 2 1 hole TBI's from a GM 2.2 or 2.4 4 banger they make about 100HP so 2 would be plenty good to feed the old iron.

All the parts except the megasquirt come out of the junkyard, I paid like under $120 for all the stuff Beater got from me. $450 for the MS, $100 for a used laptop and your injected. It can be done for under $700.


I think this would be cool, put some vintage air cleaners on the TBI's, put TBI with the TPS and IAC on the rear position (only need 1 TPS and IAC the other TBI can have these removed and the IAC hole blocked off - just goop the IAC hole full of black silcone it does a fine job. After it hardens trim it off nicely.

There are only 2 wires per TBI need to drive the injectors, 3 for the TPS, 4 for the IAC. The MAP sensor can be remote mounted and connected to the engine with a vac. line. The coolant sensor is 2 wires - easy to hide. A heated O2 sensor 3 wires. Gee that is only 17 wires. The tach input to the MS can be tied into your tach wire if your only controlling the fuel side.

If I find an old guy with a 235 4bbl locally, I'll redo the conversion that Beater and me did at B ville. The whole process took just under 2 hours including looking for some errant tools and answering a whack of questions. Its really not that hard - if you can tune solex/webbers you can tune this - need to lean a spot on the fuel curve - select that point on the fuel curve and push a keyboard button... push the save button - done.

Hey, That might just work out great on the 292. Then I could run it a while before trying the turbo. Everything could be installed except the TBI. I can do that!

That 2 1 hole TBI thing on a 2X1 manifold sounds good too. I'd like to see someone do that. 6 of those on the Big Dodge?

I like the multijector idea, so would 3X1 work for a 270 or 302?

Been there ,done that...If You think that a Predator is more of an economy-carb then that Road Demon THINK AGAIN,had one (first model=NO idle/low end-circuit,the one's that have that circuit may be a bit better...)on a 258 AMC with Crane cam and hedders some years ago and man did that engine like gas or what,with an easy left-foot and brain set at idle it still wanted 2 liters/10 km if You put Your lead-foot on and set Your brain at race-mood it easily will take 3-3.5 liters/10 km,but at that time the gas price was 30% lower than today so it wasn't that bad...

/Hans aka Speed Swede

EFI-DIY,

I would also like to know more about that fuel injection alternative you mentioned please.

Eddie