Ford Small Block 2x4 Holley Air Cleaners

[shelbydoug]

To open the discussion I have these pictures to post.

What they are pictures of are a 2x4 Holley system installed on my original block 347.

The intake in these pictures is the C60A "Trans Am" intake.

This is my '68 GT350-01107.


Hopefully this post will tend to remove confusion already installed in discussions on this forum?
A procedure that this forum is infamous for already. I apologize for adding to that confusion and this is about the best I can do to clarify.



There is some discussion about what is the "correct" air cleaner base plate to use. On my car none of the existing "factory" base plates would fit without serious interference to the firewall, the export brace and the hood base.

I can only speak of my car and presume that it is typical of '68 Shelbys and then likely '67s Shelbys as well?


There have been some comments that those base plates with this induction system fit a '65 and '66 GT350 without issue.
The only explanation that works there is that the Generation 2 Mustangs had the engine moved back relative to the Generation 1? I was not aware that the chassis of the 65-6 and the '68 do not have the same engine set backs.



The air cleaner base that I used relocated the carbs as far back as they could go and without running out and measuring, that is about 1-3/4", the distance of the centerlines on those dog leg top mounting studs. That's a big difference in engine locations in my view, but it is what it is.

If you look at my pictures, you can clearly see the rear most carb bowl under the export brace.
IF I attempt to use the '67 GT500 air cleaner base plate, the rear most portion of the air cleaner locates beyond the cowl, well past the fire wall. As it is now, the rear of the fuel bowl is about 3/4" to 1" from the firewall. This is a very tight fit.

As it is located now, the air cleaner JUST clears the inside of the hood brace structure.



For me the solution was fairly simple. That solution was to make my own base plate. It so happens that Branda sells a blank oval air cleaner plate that is easily modifiable to relocate the air clear top and filter forward for adequate clearance.

In addition to the special base plate MY set up requires those kinky 90° dog legged mounting studs. I'M SURE that they don't exist in anyone's special hardware catalogs so save your time and don't try to find them. You have to make them. 


I should also mention/acknowledge that 1" air cleaner spacers were necessary not only to clear the distributor cap, the Monte Carlo bar but also the export brace.


These pictures should give you a pretty good idea of what is going on and I suppose the complete answer to the question of what air cleaner base plate to use depends on the "chassis" it is going into? 

[shelbydoug]

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[Drew Pojedinec]

Excellent.
One question, it appears there is distributor clearance to run the carburetors forward facing.
If that was done, would the FE air cleaner base fit?

I am somewhat ignorant on sbf multicarb setups, but was under the impression the carbs were forward facing.

Thanks for the pictures and feedback!

[shelbydoug]

Excellent.
One question, it appears there is distributor clearance to run the carburetors forward facing.
If that was done, would the FE air cleaner base fit?

I am somewhat ignorant on sbf multicarb setups, but was under the impression the carbs were forward facing.

Thanks for the pictures and feedback!

Drew Sir, I only mocked up the setup with the carbs forward. I am continually hounded that I have them wrong mounted backwards. 

I stopped at not liking the proximity of the front bowl to the cap. I would describe the clearance as, "you can't put your finger between the cap and the bowl, so something like 1/8 to 1/4"?

I would guess no though. You are just relocating the metering blocks forward and not changing the centerline of the carb mounting.



Now the front mount is apparently a development in the "race" application of this manifold?
IF you look at what must be the first or original intention of the design, it appears that the heat transfer tube in the manifold is located in such a way that the front carb is the primary and that's where the choke heat passage goes, under the primary thottle if it
is backwards?

This really is consistent with what Randy said about having documentation of offering an engine at some point ('67?) with this intake for a production street car? It's also consistent with Fords procedure of not re-inventing the wheel and taking something off of the shelf that is proven in production, LIKE the 427 linkage.

My thought was just that the 427 dual four linkage works so well AND that it was STREET linkage, that I'd go that way. Certainly there is no text book that shows what is right and wrong.



There IS an installation instruction sheet that appears some where into the middle of the Ford over the counter deal that shows a different linkage and mounted forward.

In my BRIEF screwing around with that linkage, it appears that it works better if the carbs are sequential, rather then progressively opened. The secondary carb needs to open at a rate of something like twice as fast as the primary in order to catch the primary at full open together.

I didn't see that, and can be mistaken (as I often can be) but the forward mount would make much more sense for competition reasons.



Many of the comments that Mr.Gillis has made of the special center squirter, mechanical secondary carbs for this set up tend to support that view. I believe it was him that also mentioned that the vacuum secondary carbs had an issue under race conditions of too slow to close the secondaries so FORD invented these center squirters for this setup?



Personally, I'm ok with all of this, in taking criticism (it's like being married) and it certainly isn't an argument on my part (even though my wife would point out that I am always wrong and she is always right). I just view myself as somewhat of an alchemist here in trying to turn lead into gold. That's just the way I am. I get myself into more trouble then ever existed to begin with as a result?


Now we haven't even looked at how this setup would fit on a Gen 3 Mustang so there may be a variation again there? Who knows? I think though that all things considered it is a little dangerous at this point to supply a base plate to a "customer" not knowing if it will fit?


My fingers are tired now. They need to rest.

[Drew Pojedinec]

No complaints here. Just watching and learning.

I agree flipping them around "shouldn't" change air cleaner requirements, but I can say I never tried, so was worth an ask.

For a street car, I like progressive and carbs backwards.

The 3x2 sbf setup I have certainly does have the air cleaner moved forward pretty far. I'll have to test fit it and an FE air cleaner when I get home.

[shelbydoug]

No complaints here. Just watching and learning.

I agree flipping them around "shouldn't" change air cleaner requirements, but I can say I never tried, so was worth an ask.

For a street car, I like progressive and carbs backwards.

The 3x2 sbf setup I have certainly does have the air cleaner moved forward pretty far. I'll have to test fit it and an FE air cleaner when I get home.

They should give you your own shop on the boat.

Backwards works well for me but getting the float levels right is a major PITA. I'm still not sure they are?



That 427 linkage requires a bit of patience to get it right. I can see where a novice will have issues with it. If you ever set up a 48IDA Weber linkage you will learn out of necessity what "centering" the linkage means.

In reality, front or rear facing is just going to be up to the individual installer. An individual preference.

Besides possibly a mis-match of induction components, I'd suspect that bad driveability complaints from some have to do with the front v rear mounting and the linkage differences?


I'm sure we will get others to chime in here and going to get various views.



The surprise to me in this setup is how much carburetor it can take so far. I never suspected it would like the 3300/3301?

[TA Coupe]

If you follow this link to another thread you can go to the bottom of the page and see that Shelby intended them to face forward which is the correct way.
http://www.saacforum.com/index.php?topic=17347.0

I have been running mine facing forward with a direct link between the 2 for approximately 45 years on the street and track with no problem problem.

        Roy

[shelbydoug]

You had to genuflect when you wrote that didn't you?

[TA Coupe]

I've never genuflected and in this day and age if I tried my knees would give out and I'd be on the ground. The definition of my name is king so you can Genuflect to me if you want and my grandmother says that we do have a small amount of Royal blood in us from Mary Queen of Scots.🤣

        Roy

[shelbydoug]

I've never genuflected and in this day and age if I tried my knees would give out and I'd be on the ground. The definition of my name is king so you can Genuflect to me if you want and my grandmother says that we do have a small amount of Royal blood in us from Mary Queen of Scots.🤣

        Roy

It's the way you say "Carroll Shelby intended it..." Makes me genuflect. 

Personally, CS didn't know anything that his chief engineer didn't tell him about. He just made it seem like he knew everything. Just part of his mystique.

Why don't you give Remington and Cantwell as well as the mechanics working for $100 a week that actually made the detalis word, credit for something once in a while? They were just the pions in the back room? Nobody wants to talk to them? They're just lucky to have a job? Yikes. Same as it ever was Roy.



I do remember when he first started showing up at Conventions and people would ask him things like, "why did you put a roll bar in a '67 and not a '65?" He would say something like "I don't know. I had nothing to do with that."


"I've been running them forward for thirty years with no problems!" Well ya, I've been smoking three packs of Camels unfiltered for thirty years. Cough, cough! No problems. Cough, cough.
To each his own I suppose?

[TA Coupe]

Doug,  I guess your brain is adding stuff that your eyes are not seeing because I never said Carroll's name only Shelby which to me means the company. What fuel pressure are you running? I had problems until I was told to run it between you 4 and 5 PSI

      Roy

[shelbydoug]

Doug,  I guess your brain is adding stuff that your eyes are not seeing because I never said Carroll's name only Shelby which to me means the company. What fuel pressure are you running? I had problems until I was told to run it between you 4 and 5 PSI

      Roy

I guess I missed it because I was busy genuflecting? It could be the open headers or the fuel fums too? 50 years of that takes it's tolls. We were trying to count the concussions too the other day but every time I would get to 12 I would forget and have to start counting again?

I've got 5 psi at the carbs. 4 on the Webers...and Roy, not to be picky and/or lecturing, but did you happen to notice that this thread was about fitting the Cobra oval air cleaners on the 2x4 set up, not on which way the carbs go? Just sayin...


I'm curious. Do you still wear the kilt?  What about the bagpipes?