I just bought a deuce coupe that has a 392 hemi with an X3 cross ram intake and (6) 2 barrel Rochester's. The motor was built in CA a few years back by a shop that is no longer around. The setup was synchronized and dynoed on this motor. The car was then sold to someone else that changed it to a progressive setup and now does not run right. I was told the carbs had hand made jets custom for this setup. I'm looking for someone that knows this type of a setup and can help me get her back to good health. If you know anyone please help.
Since you mention "synchronized" , if I had to guess, I'd betcha it was originally set up with all stock rebuilt carbs and straight linkage. Then when the next owner put progressive linkage on it, he probably just screwed the idle mixture screws down without converting the end carbs to "dumpers" the jets are probably just drilled out originals. do you want them set up simultaneous or progressive?
I was told that this motor needed 2400 cfm to run right. That is how it was set up with the motor when rebuilt.
Have you set the linkage back to run all six at the same time???????? The linkage would have to be synchronized so all six would open and close identically. 2400CFMs, am I wrong or is that 400CFMs out a rochester two barrel??????????? Duane. ps..you may not have to do anything to the carbs, just the linkage..
if you were close to me i would get set for you Set progerssive the end carbs need to have the thicker butterflys so they would close off tight iad no idle circute then you set up the 2 middle unites this is kinda hard in the net with out know how it runs if they just turned the idle screw 's back it will leak air and be lean jim i run 6X2 since 74 progressive
I've got a Pontiac 389 with an x-2 and rochesters. It has progressive linkage and works great. The power valves are all plugged on all carbs. I used small rochesters from the '61 pont/olds 215 cu. inch motors on the centers. They are jetted around .042-.044. The outer carbs are jetted around .050-.052. If you can get an Innovate wideband O2 sensor it would help you a lot. The Edelbrock x-ram manifolds have no balance tube so it's like tuning 2 four cylinder motors. Get a VW style airflow meter to get the center carbs flowing the same at idle. You'll have to rig up an adapter to stick the meter on top of the carbs to get a correct reading. Or stick your hand over each center carb to feel the suction on those center carbs and try to get them to pull air the same. Lots of testing and tuning for idle, cruise, and wot. Let me know if you have any other questions.
NO WAY is that right. think about the engines you see with say, a 1050 Dominator on them. Is this a street engine? Rochesters are approx 275 CFM each, times six equals 1650 CFM, but all those numbers are for WOT, and for a street engine, how much time are you REALLY going to spend there? The cfm at partial throttle is WAY less than the total. I realize that the old standby "carburetor formula" leaves much to be desired in practical application, but for the sake of discussion, [392 c.i.d. x 6000rpm] divided by 3456 = 680.55 cfm again, I realize that this formula is NOT gospel, that application, engine efficiency, driving style, etc, etc, all come to bear, but even if you DOUBLE the number above, you're only HALF WAY to 2400cfm. I think the guy who gave you all the info on the intake setup had no clue what he was talking about.
I built a 6x2 setup for a 392 opened up to 450ci with lots of goodies. 6 stromberg 97s all at the same time and it put out 608 hp.. dynoed.. Duane...
After reading this comment, my suggestion would be to document exactly what you have; as any information coming from the source which mouthed that comment should be considered suspect. (1) Determine exactly which Rochesters you have. Rochester 2-G series carbs have been produced in sizes from about 275 CFM to over 500 CFM (measured on the two-barrel scale). http://www.thecarburetorshop.com/Carbshop_carbsizesandCFM.htm (2) Take off the carburetor tops and MEASURE the orifices of each jet (DO NOT TRUST THE NUMBER STAMPED ON THE JET). While you are there, check to see if the power valves are present/not present. If present, measure the orifice size of the four fuel orifices on each power valve. (3) Continuation of (1). Are all of the carbs "normal" carbs, or are the end carbs original tripower (dumper) ends? (4) If all carbs are normal carbs, try blowing compressed air through the idle ports to determine if the idle circuits on any carb have been plugged. 2400 CFM on a 392??? Yes, at 21,000 RPM. Kind of hard on valve springs! Jon.
One thing that will help is to take all the outer carbs off and block off their intake openings. Get the motor running on the center two carbs first. Then add the outers after it's running good off the centers.
I was told that with 12" of travel thru the X3 intake you loose quite a bit of CFM. That is why it requires 2400 cfm. (so i'm told). I will update I get into it with results. Thanks for the info carbking!
lol, that is funny... I don't think that's any kind of justification at all. It may get restrictive in the intake but that does not make a call for more carb.
The long runners are supposed to help develop more torque. You don't need 2400 cfm. I think this intake is a good one. It's difficult to port it due to the long curvy runners. Probably extrude honing needed for max effort. Who do you guys recommend for extrude honing?
Does this mean that if I sit 12 inches further from the table, I can eat 2 pieces of cheesecake and they will lose calories and I won’t gain weight? If the CFM is lost, where did it go? <o></o> Seriously, you are going to get some sarcastic comments based on some of the information you have been told; some more sarcastic than others. <o></o> If your manifold was an IR (individual runner) manifold (each carburetor barrel feeds a single cylinder without the presence of a common plunum) then significantly more CFM is required, as the dynamics of cylinder fill are changed. In your case, the manifold cannot be of the IR design, unless your 392 is a V-12 (6x2). <o></o> There are a number of different ways to make the 6x2 work (although never as well as a properly selected dual 4 or single 4); but then few purchase a 6x2 for performance. They look great, but you will always sacrifice some performance for looks when you use the 6x2. <o></o> There are a number of variables that can be done in different ways (solid linkage or progressive linkage; power valves or no power valves; etc.). When you pose a question, you are going to get answers from a number of different people; and while all of the answers MAY be correct for a given method; they may be mutually exclusive, depending on the methods used by the various posters. <o></o> I would highly suggest picking someone who might talk to you such as Duane (Stromberg97) who has had success with a similar project, and see HOW it was done. This way you get non-conflicting information. <o></o> Good luck with your project. <o></o> Jon.
I don't mind people being sarcastic. It's kind of funny actually. I can see if a young rookie hot rodder was trying to learn, they might get discouraged (I think that we should always support young kids wanting to carry on a tradition and make them feel good about what they are doing) however I am just trying to learn and this forum is great for that I have learned quite a bit here! This motor is in a car I just purchased and it is a all steel 32 Ford deuce coupe-Traditional 50's Period car with lots of goodies and I am only cleaning it up and getting it to drive and stop good so I can drive her the way it was meant to be. It has all the right stuff Hildebrand wheels and quick change rearend, 39 truck tranny with Zephyr gears etc... It was an original CA hot rod and it even has a original 1951 Bonneville sticker. I was big into muscle cars and now found a new love! I have a lot to learn and have learned quite a bit in the past couple years about traditional hot rods. It's hambers like you that make a difference. I will start a thread on this coupe with some pictures it is a cool piece of history! Thanks Again Carbking! I'll keep you posted!
in order to learn more about multiple Rochester setups, search for tri power threads. There are a bunch, and there is some GREAT troubleshooting and setup information contained within some of them.
Saltflatwilly. Who did you buy that car from? I think he made the back bar linkage brackets for the 6x2 on my motor. When I talked to him he said he had a 32 ford with a hemi 6x2 and I can see on your motor the same type of rear bracket for the linkage. He was from Mass. also. Curious why did he sell his car? He was very helpful to me. Hard to find linkage stuff for the 6x2 rochesters.
His name is Pete and you are right he owns a fab shop were he makes brackets and adapters and sells them.
i just became a expert!!! It makes the wall look like its going 100mpg an hour!!!!!! This runs much better
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