Inliners International Forums General Discussion Engines Carbs Holley or weber

I have a rebuild 250 t5 5 speed 12 bolt rear 341 gear with Clifford head Reworked runners valves CAM264,HEADER,INTAKE,LONG TUBE HEADER,XPIPE,
21/4 or 2.1/2 exhaust duals right now running a Holley 390 with 20 in of vacuum 9.5 power valve 54 jets. Hot rodded stock HEI. Do u guys think the weber is better easier bolt on and go more power better milage? Any thoughts I ve done a lot of work and put a lot of parts on this motor. I just want to get it running great it runs ok now but carb is my weak link right now I feel Cant get it it adjusted perfect. And have paid twice for the people companies to not get it either.

That 390 is a little bit of a bear to get dialed in. Have you thought about moving to a Clifford 2X2 with a pair of 38 mm webers. I did and was a pretty good improvement for my 261 (which I have been previously running a weiand 2X1 with adapters and a pair of holley/weber pinto 5200 32/36 carbs)

Cant get it it adjusted perfect

What list number is it?
What's it doing now?
Clifford suggests an “85” (8.5) power valve and a .048” main jet as a starting point for the #8007 list. The 8007 PVCR is .038" and may need to be enlarged with a drill.

I have dual weber 32/36's on my 292 and cant seem to get them dialed in either. I have also considered cliffords dual 38/38's. their sales pitch is good but a little pricy! is your intake heated?

The 32/36s are likely too small for the 292. I ran them on the 235 motor and they ran really well. They worked on the 261 pretty well when I first got it running and driving around but they were necked down with the adapters on the Weiand 2X1. Yes, the Clifford set up is pricy. Took me a year to save for the purchase but really woke the motor up when I installed it. My guess is that if I had installed the Clifford 2X2 manifold and used the 32/36s, would not have run well at all. Has a water heat chamber cast into the manifold.

Perhaps too small for maximum performance, but some math:
2 X 32mm with 26mm venturi = 1.646 in.2
2 X 36mm with 27mm venturi = 1.775 in.2
There are other 5200/DGV venturi sizes, less common, 23/27 and 23/29.
Total venturi area for both Webers = 3.421 in.2, about 386 CFM (rated as a 4 bbl. @ 1.5 Hg").
This is much larger than any 1 bbl. (requires 2.08" venturi), so a big step up from the OEM in all cases.
It's about the same venturi area as a big 2 bbl. with 1.48" venturis, or a small 4 bbl. with 1.04" venturis.

IMHO the adapter and small manifold size was the restriction.
292" X 5,000 RPM @ 90% VE needs about 418 CFM (rated @ 1.5 Hg" for a 4 bbl.) or 591 CFM (rated @ 3 Hg" for a 1 or 2 bbl.).

When I jump on the gas from shifting I have a slight lean spot or surge. The Holley power valve video says cut vacuum pressure in half and thats power valve size. Vacuum is 20 I did run a 6.5 and 8.5 I think numbers were hard to read. Now 9.5 running better than before but guzzles gas.
I did start out with a 51 main jet ran strong but had a very bad lean stumble when getting on gas from shifting. I increased main jets till stumble was hardly noticable but still there.
Ive had as high as 160 no stumble but doesn't have the performance motor had with lower lean jetting sounded like it ran better.

That advice (1/2 the reading) is too general. The power valve choice should be based on a figure slightly below your highest cruising vacuum. A high number will open every time you touch the gas and kill your mileage, a low number will give a flat spot on acceleration.
Important: the PV number has nothing to do with jetting, it's not how much fuel is added. This is entire controlled by the power valve restrictor channel, which is 2 holes drilled in the carburetor body inside the flat bowls. The main jet only controls cruising mixture, all enrichment is added by the PVCR. The different 390 models have different PVCR, and will have very different full throttle mixture with the same main jet.

What is the list number?

"IMHO the adapter and small manifold size was the restriction."
I believe so too. any advantage with clifford shorty headers over the langdons? they had a package deal with headers, intaje and carbs.

the 5200 is a progressive two bbl. the 38 mm Weber is not. So the adaptor was somewhat of a restriction on the 235. On the 261, the 5200s still ran well even with the adaptors but yes, I am with .you, would have run better if on 2x2 intake. The 38 mm runs better throughout the rpm range, a lot better. I have Clifford long tube headers for the sound. The shorty headers should similar

Even some existing 2 X 2 manifolds have openings much smaller than you want. The Edmunds looks like 2 X Stromberg 97, which is only 1-19" (30mm) ID each hole.
Did Clifford make a 2 X Holley 2 bbl. for the 235?

Not historically but the new intake has adaptor plates to mount the Weber carbs. It’s the same set up as their older 2X2 2X4 intake for the 230/250/292. What I don’t know is whether the plates to mount say a pair of Holley 2300 carbs for the later motor will bolt on to the new 235/261 intake. I never gave it a though to chalk as I have one of cliffereds early style dual carb intake for the later motor and the Holley 2300 plates.

I googled around for some images of 2 X 2 Webers, and all of them based on an existing 2 X 1 manifold had the entire 77mm X 36mm "window" (output side) of the DGV choked down to the #3 SAE 1-9/16" intake flange, only 2/3 of the Weber throttle area.
Better, but not as good as it could be.

4160 is list number

I mistakenly gave my input to this Carbs subject under the Performance Pushrod subject a day ago..

My input was that I had similar experience dealing with a Holley 390 carb on a 302 GMC. It bogged down just after takeoff. I went thru 10 power valves but could not fix the bog. The Holley transition from low to medium speed was the problem.

I have run 3 32/36 Webbers on my GMC 302 for 24 years with no bogging problems and good performance. The low to medium speed transition is smooth.

If you're using the Holley 390 with vacuum secondaries, delete the power valve entirely, richen up the jets by four steps to tart with and switch to the big accelerator pump assembly. You can adjust the pump squirt with different cams to handle acceleration and adjust the main mixture by making the jets larger or smaller as needed.

The mechanical secondary is a little more tricky because you have two accelerator pumps and two more squirters. It is more sensitive because everything works off of the throttle linkage, so you have to compensate more on pump and secondary timing.

The NASCAR 390 is even a little more persnickety, but it is another animal altogether.

If your engine ever backfires with power valves, they will most likely rupture and leak or fail to open properly because of the leaky diaphragm.

Clifford. Dedicated 2X2 intake for 235/261. Uses flange plates to mount the Weber’s.

I think I see something odd.
Clifford sells a complete 38/38 (simultaneous linkage) package, but the progressive 32/36 (Pinto) is not listed.
Did his 32/36 kit include 1 DGV and 1 DFV (left & right hand opening) carbs?
Anyone who has used another manifold with adapters: did you use both DGV?

Clifford may sell just the intake and the bolt on plates. You would have to call. They only advertise the complete set up (I think the deal is that Larry resets the floats on the 38 mm, and bolts it all together, makes initial adjustments. That is how I bought mine.). The Clifford is a sort of modular set up. You have the intake, and then flange plates bolt to the intake depending on what carbs you are using.

On the Clifford dual carb manifold for the 230/250/292, you purchased flanges for either a pair of 2300 Holley carbs or the flanges for a pair of 4 bbl. carbs.

So on the 235/261 set up that they advertise, it comes with flanges to use the 38 mm Webers. But the stud spacing is the same as the 32/36 Holley/Weber 5200 (and I assume the Weber 32/36) so theoretically you could use the 32/36 Webers on the Clifford dual 235/261 intake. What I don’t know, and it’s my own fault, is whether the flanges for the 230/250/292 dual intake will bolt on the the 235/261 intake. I have the flanges for a pair of Holley 2300 for the later dual manifold. I just did not think to see if they would bolt up when I had my new manifold apart for cleaning before I installed it.

Now, the thinking might be that the 32/36 would be a little better suited to a 235 motor. Small primary progressive carb. But a friend of mine has the Clifford set up on his 57 vert with a 235 and his motor is a lot milder then mine is and he claims it runs great on the dual 38 mm carbs (non progressive).

If I am not mistaken, Edmonds had a 235/261 intake that used two stromberg two bbls. There may be others that used those carbs I am not sure. But to my knowledge the Clifford is the only currently produced manifold to use two two bbls. All the others you have to use an adapter 2 into 1 to use the Weber 32/36.

My original set up was a Weiand 2X1, adapters, to 74 pinto carbs. Fuel lines to the outside as the jets are in corner floor of fuel bowl. If you mount them the other way, you run the risk of uncovering the jets and getting a bog. Tom Langdon told me he ruined a couple of carbs drilling holes to get rid of an bog on hard acceleration before he realized the carbs needed to be mounted differently.

So I have run both set ups. The dual 38s run better. I would be happy put a couple of photos of my set ups but I will need someone to post them for me as I don’t have my photos on a host site.

Mike

(My original set up was a Weiand 2X1, adapters, to 74 pinto carbs. Fuel lines to the outside as the jets are in corner floor of fuel bowl. If you mount them the other way, you run the risk of uncovering the jets and getting a bog. Tom Langdon told me he ruined a couple of carbs drilling holes to get rid of an bog on hard acceleration before he realized the carbs needed to be mounted differently.) not understanding about the bog and running fuel to the outside, how you mount the carb or which side of fuel inlet? I am using 2 of these on an offy w/adapters. fuel inlet on valve cover side and linkage out, reverse opposite Clifford set up. https://www.ebay.com/itm/Weber-32-36-DGE...3XS&vxp=mtr

The adapter method does restrict air flow to some extent, but also insures the mix enters the manifold in a (presumed) good location w/r/t distribution.
Almost all of the 1 X 2 DGV conversions for L4 engines have the carburetor sitting across (90 degrees) to the crank, with the primary next to the engine.

I can’t answer for the genuine Weber 32/36, only for the Holley Weber 5200 variant. The jets are located in the bottom of the fuel bowl on one side. So if you mount them with the jets toward the front of the motor, on a hard acceleration or launch, the fuel sloshes away from and toward the back of the carb and uncovers the main jets for just a bit, enough for a bog. If you mount them with the jets toward the back of the motor, on acceleration, the fuel is now sloshing toward the jets and no momentary uncovering.

4160 list no

That's a category which has a secondary metering plate (instead of the 4150 with a block with jets and dual floats), in many sizes, not the list number.
Common 390 list numbers:
8007 with .038" PVCR (common for L6 and small V8)
6390 with .031" PVCR
R6299-1 with .021" PVCR (for L4 engines)
Remember that the size shown supplies fuel at WOT proportionate to the square of the ID: the .038" is 150% as large as the .031" and 300% as large as the .021".

The final WOT fuel is the total of main jet + PVCR. If you increase main jet to size to compensate for a small PVCR, your gas mileage goes away.

Mine is 8007

AFAIK that's the most commonly used model, shouldn't be anything that can't be fixed.
The big main jet is where your mileage is going.
Tried raising the float level?
What fuel pressure?
Where is your idle spark set?

Main jet is 54
Floats are set per instructions on Holley site I could double check?
Mechanical fuel pump stock style but new 5.5 lbs rated
700 rpm idle its a manual
12 deg timming Big Hei remote coil with a cut off vacuum plate
NO HEAT TO INTAKE I LIVE IN SOCAL

Another possible cause of the bog: your secondary opening rate is controlled by a vacuum diaphragm. Holley makes an inexpensive kit with different spring tension choices - a stronger spring may fix that by delaying secondary opening until engine demand is higher.
http://tinyurl.com/y8thdk2a

.048 to .052 isn't 4 sizes, it's 12.5:1 instead of 14.7:1 cruising mixture, and when combined with your .038" PVCR it's 10% richer WOT (13.0:1 becomes 11.7:1 A/F).

currently have both dgv's on an offy, had small carter webbers from langdons. originally linkage pulling in line/front to back, then switched to parallel/pull from side. have pics of all 3 setups but don't know how to post pics here?

e-mail them to me jdiamond (at) optonline.net

Use the same format with your file names

first pic is pulling front to back, a linkage nightmare that physically could not open carbs fully. the design of carbs needed around 120 degrees rotation from idle to WOT. not an issue with the 32/39

for pics? I have them stored on computer, the prompt asks for a web link?

Sent if u need more pics or different let me know

I put 53 m j and a 8.5 power valve. When your cruising and let off gas and get back on gas this is where my stumble or lean bog happens. So I switched back to 9.5 power valve and lean bog got better but still there a little. It doesn’t do it from a start going threw the gears flooring it and shifting their gears. Only if u let off gas then get back on gas this is where it happens. This is driving me crazy. I’ve bought all these Clifford hop iup parts and built this motor around all there specs from the website and Larry down there I had his machinist build my head. And the one carburetor Garou one guy that was supposed to be able to work the Dyno tune and it’s still not right.

How much fuel pressure are you using - at the carb inlet?

New mechanical pump rated 5.5 no gauge. Tonight I tried out different spray nozzle went bigger first a 35 had a 31 in there and it got worse so I went opposite smaller to a 28 and hesitation still there but I like the way it revs with the 28 so I'm leaving it in seems quicker.
If I drive with a slow pedal to floor motor is smooth strong and quick. If I stab throttle while driving always a slight hesitation then motor revs. And I'm using pink pump cam in #1 hole. Right now just throwing parts at it.
I noticed Clifford no longer has the Holley on there website. Pushing single and there new dual intake with 2 Webers with gains of 120%.
Tempted Just to get this Is this a great set up?

"Gains of 120%": when installed with every other part they make.

Yeah I have all those other parts. Just can’t get this Holley dial in.

How hard would it be for you to run hot water to the intake?

Would have to switch intake or weld water plenum under intake. My vac at idle is 22.
Today I went back to Clifford starting jets MainJet 48 squirter 31 power valve 8.5
and had lean stumble off beginning of gas pedal press. When I put in 9.5 it was better when I put in 10.5 it worked great but still had a slight one so I installed 49 main jet it was better but ended up leaving a 50 main jet in and I liked the 28 squirter and took out pink cam and left orange in. I am really happy with my seat of the paints one circuit at a time till I got my best results so far.
700 idle manual Trans 50 main jet 28 squirter 10.5 power valve and orange pump cam in #1 hole
Rebuilt chevy 250. Rebuilt head with Clifford's valves and runners cleaned up. Clifford long headers. Clifford older intake no water. Holley 390. X pipe dual 2.25 pipes with 3 chamber mufflers.

Have you tried all the stock jetting and power valves - and just put in a #37 squirter? Worked for me.

After all that tried every combo under sun but 35 squirter was biggest I tried and it was to rich. But now I think of it my main jet was a 53 at time so I could try that also. LOL
The leaner set ups worked best except it liked the bigger power valve. I ll give it a shot it isn't going to hurt I tried every other combo.

Again: the power valve isn't bigger.

Yes its a what vacuum it comes in at I herd please correct if Im not getting it. IM pulling 22 vacuum at idle so I cut it in half per Holley instructions. I put all my squirters in from 28 to 37 still has off cruising surge when u give it gas in one spot of throttle. The bigger main jet I install gets rid of it. Ive gone as high as 60 main but it just destroys power. The 3 chamber muffler has a certain tone u can feel and hear when u run a good leaner jetting and the power is good. Except for that spot or surge if u press gas pedal real slow u can over come it or get threw. There has been many other post I've read with real close situations but no one ever puts what cured there issue.

OK I have to take back some on my previous post because they were incorrect I did some more investigation today found out my fuel pressure at carburetor is one and a half pounds my vacuum gauge was not Sarah without broken got a new one not pulling 22 inches of vacuum pulling only 15 I’m going to first take care of the fuel pressure then I’ll take care of the power valve. So I just finished new fuel pump mechanical runs between 4 and 5 at idle. did change power valve to 7.5 per 15 in of vacuum but still has same thing same spot. So I guess I'm forced to look at power valve restrictor hole or channel?

So I take truck in to BILLS DYNO today. He's been doing carbs for 40 year and has equipment to measure air fuel. After all I did it ran good all the way over there but still had small nose dive when u stab gas pedal. He first set up idle a little leaner than I had rechecked timing and said it was good. He then visually checked and made sure squirters were shooting and he said the little nozzles on squirters on certain carbs he liked using squirters without nozzles he feels the shooting right in to gas stream and end up over rich condition so he put 25 squirter without nozzles and truck left his shop running great.
New fuel pump and resetting valves didn't hurt. Should have got a print out for horse power and torque but gear broke on dyno that runs that part of it. First time was around 200 hp and 275 torque at rear wheel original motor was 150 horse power I think but at crank.

Cool little vid-series on Weber DG series

https://www.youtube.com/watch?v=A44-xG3pKlY&t=11s

https://www.youtube.com/watch?v=fhYSo6u-Jm0&t=75s

https://www.youtube.com/watch?v=BfIH26O2Ijg

for the 32/36 guys, look at vid 2 and the sync link kit! may help drive-ability

I ran a number of experiments before discovering my biggest problem was timing. I still need to get my distributor set up, but higher timing made a huge difference.

It's still in pieces, but when I took it apart, I was running super rich. Front two plugs are very black. I'm backing off on things. I'll probably go to PV 8.5, MJ 51 (original). It's a gas guzzling pig as it stands.

Current settings (too rich)
○ Power valve 9.5
○ Main jets 54
○ 35 accelerator
○ Secondary jets 59
Timing now set to 18 BTDC (no vacuum advance)

That PV means that whenever you touch the throttle (reduce vacuum below 9.5) the PV opens - there goes your mileage. What's your vacuum reading at constant 60 mph?
Changing MJ size affects cruising mixture more than WOT mixture.
To get lean cruise mixture: small MJ.
To enrich WOT: enlarge PVCR.

I discovered that I had a 58 MJ in, way too big. Changed back to the original 51,sticking with 9.5 PV. I had originally found 51 pretty lean, but I was still using the 6.5PV at the time, and hadn't gone with more aggressive timing. Hoping that works. I seem to remember my vacuum being something like 22.

I give up

Hey, I don't know if this was intended for me. My engine is on a stand in the garage awaiting its new oil pan gasket. Hard to try anything out or get more data. I was changing jet between coats of paint.

The PV should be less than half the vacuum at cruising. I tried 10.5 at one point because the vacuum was around 22, but that didn't seem to help anything. I couldn't find my 8.5, think I have it to somebody. 6.5 was what the carb came with. Found what I had written down in my log didn't match the jets. Need to get this all back together and running so I can get back to the ignition. If like to try having that trimmed, but don't want to do it before I try these things out.