Sidewinder fuel distribution

[allrightmike]

    Hello all, I am new here so this post may not be quite up to speed. I have been reading Jay Brown's intake comparo book with great interest. In regard to the sidewinder intake fuel distribution problem; in 1967 I put one of these manifolds on my 390 mustang. At the time the word was that the carb. offset to the left was done to equalize fuel mixture on the NASCAR tracks where centrifugal force from turning left caused the right hand cylinders to run rich. I figure I might be just old enough that maybe others never heard this theory. Any comments?

[My427stang]

I heard that too, been the going story for a long time.

I am not sure I buy that it worked, but it could have certainly be intended to do that.

One thing I never did was look at where the long runners were in the firing order, could have easily been to make a broader torque curve too.  Some long runners, some short runners for a flatter but broader usable curve.  If they were in order, that wouldn't jive, but if it worked out that it coincided with firing order, it would make sense

[1967 XR7 GT]

Here's the flow chart from when JDC Ported my manifold and a picture of my manifold for reference, the chart shows the different before and after flow numbers for my  "J" sidewinder. Jay noted in his book during the testing the right side showed lean & the left side was rich. 1&4 and 6&7 on the upper chamber and 3&4 and 5&8 on the lower chamber, what's clear in the picture the larger runner volume on 1&4. Firing Order: 1-5-4-2-6-3-7-8

[Drew Pojedinec]

Have you guys tried running the CJ carb or a CJ replacement -U carb?

They have cutouts in the downlegs that compensate for a distribution issue.  The primaries are bell boosters, but presumably a person wouldn't have distribution issues due to the high vacuum at cruise when the mains are online.  At WOT when vacuum drops the secondaries with their cutouts would direct fuel in a direction to force the fuel into lean runners.
Pictures included to demonstrate.

IMG_0621 by Drew Pojedinec, on Flickr

[My427stang]

Look closely at that intake, pretty much all the runners are "long" if you follow the firing order and where they go to.  It would be interesting to run a string to plenum entry on each port.  Maybe it was a way to get all 8 closer?

[Katz427]

Thank you ,Drew, for that picture. I do remember the cutout boosters.
FWIW a gent who did the carbs on our sportsman car, related to me about the problems they had getting the jetting on the NASCAR Ford's. He seemed to always have staggered jetting in the carb. Roy told me that the dual 4bbl setup allowed in 1967-69 made the jetting situation easier. It certainly has been a while since I have seen the boosters modified like that.

[Rory428]

I do not run an A/F ratio gage in my Fairmont, or never had my heads or intake on a commercial flow bench. That said, my Fairmont ran its quickest and faster 1/4 mile numbers with a Sidewinder intake , that was port matched to my stock iron CJ heads and had the center divider cut down.I guess if the Sidewinder has known to have problems, my engine never got the message.

[jayb]

    Hello all, I am new here so this post may not be quite up to speed. I have been reading Jay Brown's intake comparo book with great interest. In regard to the sidewinder intake fuel distribution problem; in 1967 I put one of these manifolds on my 390 mustang. At the time the word was that the carb. offset to the left was done to equalize fuel mixture on the NASCAR tracks where centrifugal force from turning left caused the right hand cylinders to run rich. I figure I might be just old enough that maybe others never heard this theory. Any comments?

I heard that same thing while reporting those test results on the old FE Forum, and it makes sense, but since I couldn't find any concrete evidence or written documentation backing up that story, I didn't mention it in the book.  One thing about the sidewinder was that it didn't really seem to care that it was running lean on one side.  It wasn't lean enough to cause damage, and a normal Holley carb calibration would have probably ended up working fine, despite the fact that one side of the engine was running leaner than the other.

Another point in favor of this theory is the sidewinder 4V SOHC intake, which exhibits the same characteristics as the wedge sidewinder.  For sure, that intake was designed for NASCAR also.  Ford did it for a reason...

[allrightmike]

  Thanks everyone for the response. The 390 seemed to like the sidewinder intake along with a ford c/sa cheater cam adjustable rockers adjusted to the top of travel and about .080 off the heads. Would run 13.90 at 101 with stock exhaust. Beat every 396 chevelle in town!
Mike.

[cammerfe]

FWIW, I have had experience with one of the very first Sidewinders cast. I was involved with one of the first dozen CJ Mustangs---a 'dollar' car. One evening, in the shop, Jon Corrunker and I were doing something-or-other when we were visited by Jack Roush, at the time the President of the High-Risers, and Al Buckmaster, the guy most responsible at FoMoCo for manifold design. They brought us a new casting from the experimental foundry at The Rouge---a Sidewinder. It had been tinkered with in so far as to have had a fore-'n'-aft divider welded into the otherwise open plenum and material added to the bottom of the runners at the head-manifold interface. We were told it needed final touch-up before being run. The divider was to make it work better with our auto-trans car. The open plenum was done with a stick car in mind. We never did use it on the CJ. I finally finished it and put it on my '67 Cougar XR7 GT/427. The plugs showed even burn from side-to-side. I used a carb I got from Hal Droste, the Holley guy who actually went to EEE every day.

KS

[Clark Coe]

Is there an industry standard for measuring intake runner length?

I can help the Sidewinder discussion by measuring the individual port lengths of the unmodified Sidewinder (revision J) intake that is setting on the shelf in my garage. But am not sure where the beginning of a port is and where the end point would be?

Could project a vertical line straight down from the carburetor flange opening to the plenum floor and start there?  The runner centerline would be the best, but difficult to determine the exact center position.

[RJP]

Have you guys tried running the CJ carb or a CJ replacement -U carb?

They have cutouts in the downlegs that compensate for a distribution issue.  The primaries are bell boosters, but presumably a person wouldn't have distribution issues due to the high vacuum at cruise when the mains are online.  At WOT when vacuum drops the secondaries with their cutouts would direct fuel in a direction to force the fuel into lean runners.
Pictures included to demonstrate.

IMG_0621 by Drew Pojedinec, on Flickr

Along those same lines of fuel distribution Holley did something similar with the 3310-780cfm on OEM equipped 396/375 hp BBC. The primary boosters [down leg] had a small "finger" on the outside diameter of the booster supposedly to correct a [part throttle?] lean condition in a couple of cylinders on GM's dual plane high rise aluminum manifold. Drew, do you have any of those carbs for a picture reference?

[Joe-JDC]

Is there an industry standard for measuring intake runner length?

I can help the Sidewinder discussion by measuring the individual port lengths of the unmodified Sidewinder (revision J) intake that is setting on the shelf in my garage. But am not sure where the beginning of a port is and where the end point would be?

Could project a vertical line straight down from the carburetor flange opening to the plenum floor and start there?  The runner centerline would be the best, but difficult to determine the exact center position.

Yes, measure the inside length and outside length.  Add together and divide by two.  Intake length runner lengths are determined by cubic inch and intended rpm of a particular engine for the harmonics of that particular engine.  Packaging of older engines under streamlined hoods were a bane of many intakes before EFI.  Joe-JDC

[Clark Coe]

Joe, Where do I begin measuring in the plenum? At the vertical shadow of the carburetor mount opening? Top center and bottom center of the cylinder head/manifold mating opening?

It is curious to note that my Sidewinder has exhaust heat path through the manifold....odd for a NASCAR race manifold.

I have a engineer friend that had a decades long career in Detroit designing ever more compact front accessory drives for automobile engines. All in an effort to lower the hood and front profile.

[Drew Pojedinec]

Along those same lines of fuel distribution Holley did something similar with the 3310-780cfm on OEM equipped 396/375 hp BBC. The primary boosters [down leg] had a small "finger" on the outside diameter of the booster supposedly to correct a [part throttle?] lean condition in a couple of cylinders on GM's dual plane high rise aluminum manifold. Drew, do you have any of those carbs for a picture reference?

Of course I do....
These are on the original 3310EH carbs, they are called Spivies.  If a person is interested, they can do the same thing with a small zip tie

IMG_0535 by Drew Pojedinec, on Flickr


I'm a huge fan of the EH carbs, they run really really well on everything, and they sure do clean up nicely.
The fact that I regularly find usable cores to restore for $60-$80 really helps things too.  Can't go wrong with them.
IMG_1132 by Drew Pojedinec, on Flickr