How realistic is it to run 4X2's on "street" flathead?

Hey ." HOT ROD FREAK " . Where did you get those groovy finned head covers ?

 

Very clearly said, I agree with this, and maybe the approach would be to run the 4x2 and block the fuel supply to the second or third carb or even both and run on 2 or 3 carbs. You get a great looking motor and maybe more even performance.

 

Call me a grouchy old fart. or whatever, but I'll be damned if I can understand how the last post on this thread can come from anybody with any reading comprehension at all.
Not after Bruce has done an excellent job of explaining that 4-2s on a flat motor uses a manifold that basically creates 8 IR throats with only small equalizer passages between the throats and Flat Ernie has related hands on experience with these 4-2 setups and that they require straight linkage and an operating carb throat at each hole or they won't work and I myself have related that all of these 4-2s I've ever seen were on straight linkage!
Sometimes I wonder why we bother!
Dave

 

I think there has been several threads on this before.
4 97's or 48's work fine on the street.
I have set up about 40 of them over the years.
Straight linkage.
In the 50's I drove mine to work 5 days a week, raced on weekends
and in August of 1953 drove it to Bonneville, ran all week and drove it home...Best time was 130.03.
Go for it.

 

Hey, Pete, can you talk about tuning issues on these things? My thought is that 1 barrel/1 cylinder can lead to some fierce pulsing at some speeds without a plenum or other cylinders to control things. Air that goes in-out-in can obviously pick up more gas than it should. What did you go through taming the metering needs?? I haven't gotten hold of a 4 yet (anyone need a triple and want to trade?) but the idea is interesting, especially after reading some IR stuff by Vizard.

 

You can run four 2s easy ,on the street in a heavy vehicle .this is how its done .Make a 4x2 box section plenham to bolt to the 4 carb manifold using extended studs right the way through .Dont forget to get it milled flat.Check that all the holes match up.Paint it silver and with a progressive linkage ,this has no flat spots.Check jetting .

 

Bringing this thread back from the dead. Let' say the 4 barrel manifold for the flathead uses the 390 cfm holley, wcfb, or up to 500cfm with a common plenum. The true IR runner systems start basing the choke size on the intake valve diameter. On a scale of 1 to 10, where would the Edelbrock 4x2 be gauged as being close to a IR intake? By looking at my 4x2 intake MOST of the path is a straight shot from the carb base to the valve. There is a plenum balance area between all carb pads, but they are very small; like ring finger size. My point it is, if it breathes almost like a IR, one could use 4 carbs with their total cfm being higher that a single 1x4 carb. Bruce, Pete1 any feedback??

 

Pics?

It's possible, but the mixing and matching of carbs make a very important factor in the build, because the right size for your engine might be a little hard on the wallet.

Or do you have the carbs?
How hot is the flathead? Manual or auto? Roadster or truck?
Do you drive it like you are sixteen all over again?

 

This is a hole different animal I am working on. Mild flathead, manual trans, light car(eventually). Not going to be a hard driver with this one. These carbs have the adjustable choke feature, but the smallest choke is still a bit too large. I can have custom chokes made to 28mm, which is close to the cfm of what a wcfb would flow. But since my 4x2 intake is more like a IR rather than a 1x4 plenum, the chokes could be opened up a bit, to maybe 32-33mm. Other jetting in come in after choke size is established.

 

what day month year has your flatty been casted and rebuilt?

 

Why not put 4 dcnf webers on this manifold and tune it as a true ir induction.


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