Best actual Ford cast 4V intake found

[Joe-JDC]

As many of you know, I have been porting since 1972, and specializing in Ford products, but branched out to anything needed, even tractor heads,  even four cylinder, six cylinder, and SOHC/DOHC late model heads, etc.  I thought I had ported every Ford cast aluminum intake that has a Ford part number on them, until last month.  I now have had two C6AE-9425-K "Sidewinder" intakes to flow and work on.  I had never seen one of these, and I have ported a lot of -"J" Sidewinders over the years.  These two "K" intakes average 338-339 cfm as cast.  That is better than the "J" intake by at least 30 cfm, and 40 or more better than the -F.  Better than a Performer RPM as cast, and better than the BT as cast.  How many of you actually have one of these?  Supposedly came on a few real 427 Fairlanes, and 427 Cobras, but I have not verified that at this point.   I would be interested in buying one if I could find one reasonably priced to add to my collection.  Joe-JDC

[cleandan]

Sorry Joe, I don't have a (K) sidewinder.
I am curious what you found in the casting design that gives the better flow ability?

[Joe-JDC]

The distance between the pushrod tubes is over 1.500" allowing for wider ports as cast for one thing.  Has some unique features that make me wonder if they were meant for marine usage, also.  Joe-JDC

[Joe-JDC]

Hit post accidentally before adding pictures.  The studs on ports #1 and #5 are unique to Ford intakes that I have seen.  Joe-JDC

[Jim Kramer]

I have two sidewinders, a "J" and a "K". The J has had some home porting done on it, so I can't compare the ports, and I've never ran the K on anything so I can't offer any info on it performance wise. One thing I will say is that the one you have there is a lot cleaner than mine ..........Jim Kramer

[RJP]

The distance between the pushrod tubes is over 1.500" allowing for wider ports as cast for one thing.  Has some unique features that make me wonder if they were meant for marine usage, also.  Joe-JDC

I doubt they were for marine use as aluminum does not get along well with raw sea water, salt or even fresh water. Marine intake manifolds were almost all iron. Only departure from iron was with crate engines that wound up in hot boats such as Sangers, Hondos, Rayson Crafts etc. In the 60s I remember crate engines stacked up in the Vic Hubbard's warehouse as they, V/H were big into the V-drive-hotboat scene. That would be about the only use of any aluminum manifold used in marine application that I am aware of. Boat builders such as Chris-Craft, Stephens, Tollycraft, etc usually used the marine/industrial FEs that were the complete marine package consisting of iron water cooled exhaust, marine cooling systems [both closed or open systems] cast oil pans, and front & rear mounting, usually cast in iron as well. Weight was not a big factor in say a 36' Chris, Connie using twin 427 engines, one being a counter rotating engine.   

[Joe-JDC]

Years ago, in early '70s, there were about 40 or so of the 427 engines sold for use on Lake Havasu boats with the aluminum heads with the "X" on them.  They were sold as GT-40 crate engines.  I had the aluminum heads in my hands back then, and they were really porous, as history will acknowledge.  I am just wondering if the intakes on those engines were the "K" variety.  What stumps me is the two raised studs on the intake ports.  Anyone know what they were used for?  Especially the #1 port.  Joe-JDC

[Stangman]

Best guess on #5 is coil bracket and #1 an accessory mounting spot. Of course that’s a guess. Joe do yo have a pic of the two manifolds right next to each other, the K manifold looks like the upper plenum are huge. I have an F-427 and that looks bigger

[427John]

Years ago, in early '70s, there were about 40 or so of the 427 engines sold for use on Lake Havasu boats with the aluminum heads with the "X" on them.  They were sold as GT-40 crate engines.  I had the aluminum heads in my hands back then, and they were really porous, as history will acknowledge.  I am just wondering if the intakes on those engines were the "K" variety.  What stumps me is the two raised studs on the intake ports.  Anyone know what they were used for?  Especially the #1 port.  Joe-JDC

Maybe for mounting the fuel log used with Le Mans bowl Holleys used on those engines?Or possibly for the turkey pan that surrounded the carb?

[Joe-JDC]

I do not have a picture of the two side by side, they came to me at different times.  I think I will take a picture tomorrow of a RPM, BT, and this K side by side.  The plenum is huge, for sure.  Joe-JDC

[mbrunson427]

We have both, I'll pull them out of the mezzanine and take some side by side pictures. I had never noticed any difference, but now I'm curious.

[gt350hr]

    The manifold was used on Nascar engines. Special parts at Ford had to be "funded" by accounting before they could be made. Dennis K might be able to see the original blueprint and the notes on it.

[1967 XR7 GT]

Hi Joe

Question: You said the "K" as cast flows better than the "J" by as much as, at least 30 cfm & 40 or more better than the "F", my question is
about the finished porting, is the "K"'s ported flow better than the "J" & "F"'s ported flow ?  Or is it just the as cast flow, that's better ?

And is there any difference in the "J" & "F"'s ported flow ?

Thanks

[Joe-JDC]

The "K" ended up about 20 cfm better average than the "J" sidewinders.  It is difficult to get a -"F" to average over 360 or so.  The "K" beats that by over 30 cfm after porting.  Joe-JDC

[Jim Kramer]

I can't tell ant difference