Technical 4x2 Carburetor Question

possibly got the 4&1/2 lb to 9 lb version ( p/n 12-803 not 12-804 )

^^^^correct, no more than 3lbs.
Also float levels are important, as you no doubt know.

There has been some debate about whether you need a bypass on those to make them work correctly.
A bypass may also help with the leak down issues commented on in post 3 and possibly vapour lock.
From reading a lot of comments on here, (a few years ago), about half had no issues and half did. Maybe because of too much pressure from aftermarket pumps.
Very few market it this way, but the Holley website says that the Fuel pump can’t be pushing out more than 7lbs for your regulator.
Some info here -
https://www.holley.com/products/fue...regulators/carbureted_regulators/parts/12-804

 

did you resolve your carburettor issues ?

 

I've been struggling with similar problems on a 331 Hemi with 4 97's on it. I struggled with leaking needle and seats and have solved that issue, but am still not really happy with the way it runs. I know it is way too much carburetor for this engine but want to keep it for other reasons. If I had a different arrangement, I could use a progressive linkage, but the way mine is set up, it would cause some severe fuel distribution problems.
Has anyone ever tried closing off one of the two fuel mixture screws on each carb to limit the amount of fuel at idle?

 

I would not think that the 4 97's are too much for that Hemi. They flow at 155 cfm's or 620 in total. What jets are you running 45?? Your idle circuit runs thru the jets. I would step the jets down if it is running rich. Good operation analysis is in this video from Charlie Price. He speaks of the main circuit and idle circuits around 5:50 in the video.

Are these new Stromberg carbs or the knock offs offered by other outlets?

 

GasGas, forgot to mention that those air cleaners have been noted as being quite restrictive. Might be adding to the richness.

 

StrayCat, you said you are running the A tank. What filter are you using to filter the gas? Is junk getting thru to the seats?

 

A small return line to the tank with a small orifice will bleed off pressure when the pump stops, AND keep cool fuel from the tank circulating by the bowls. Malpassi makes a good regulator found on Porsche and VW sites.

 

These are the real stromberg's. I got them from a guy on this forum who is the distributor for them. I learned the lesson on the china air filters. Ended up using some K&N style foam ones. Now, I get the same performance with them on or off. Running right at 2 PSI fuel pressure and have used a vari-sync tool to balance the carbs at idle. I've been thinking that I might have the idle set too high -
+

 

Run a electric fuel pump with a manual off switch, when you park turn off the pump and let the engine run a few moments to alleviate some of the line pressure.

.

 

So, new 97's from England then with 45 jets? I would try 43 or 41, maybe hook up a wide band sensor to check the results.

 

I have a question about this topic. I’m planning to run weiand 4x2 intake with 97s on my 270 Red Ram hemi. There has been articles about this set up and they recommend to run 2 middle carbs as primary and 2 end ones as progressive. That makes me wonder about fuel distribution, for sure cylinders 1,2,7 and 8 will not have as good fill as middle ones, but with modified better sealing butterflies in end carbs that might not be big problem. But they also recommend to leave accelerator pumps unhooked in end carbs. That makes me wonder, doesn’t end cylinders run way too lean when you floor the pedal, and they have full air flow but not any fuel cause vacuum is zero. Middle carbs can’t feed them in this situation, can they?

Do you guys have any experience with this set up? I think it would be better to run all carbs as primary, or at least keep pumps hooked in every carb. What are you thinking? Should I just do as recommended and leave the thinking to wiser men?

And make clear, I’m not after smooth and low idle or max performance with this set up. It can be little rough, cause it will be a hot rod not grocery getter, and the looks are better than with single 4 barrel intake .

 

I would send Uncle Max an email at info@97-express.com and see what he would recommend. I would think that running non progressive would be much easier overall.

 

I would run them in sync and jet accordingly.

 

Thanks for the comments! I will ask Max his opinion, but it seems that you are thinking like me: all carbs in sync and find right sizes jets and powervalves.