Original 289 Trans Am Intake "Linkage?"

[Starliner]

I am using an Old original Trans Am 2x4 Intake, (2) 390 holleys ( late carbs). 2 questions if someone can help?
( Randy ?)

1. Can this intake be used with a progressive linkage?  Meaning running on the front carb primaries only?
  ( No sure if the Intake needs both primaries opened to feed all 8 pistons at idle)

2. What Linkage do I use then and whom sells the smaller throttle studs to utilize the slide linkage bar? If this is the right piece.

Thanks for any advice

Joe

[shelbydoug]

You have two choices.

You can use the 427 Ford low rise linkage which puts the carbs backwards or the 289 Trans Am linkage which puts the carbs forward.

You can get both at various vendors.

Here is one. Carls Ford Parts.

http://carlsfordparts.com/main.html



You might want to try both to see which you prefer?

Both are progressive and idle the engine on only one carb. The secondary carb starts to come in around 3,000 rpms.

Mounting the forward puts the primary carb up against the distributor cap and the choke way in the front of the engine. It's a simpler linkage and for racing purposes works better since most of the time the throttle is at WOT.



The 427 linkage is a street linkage used and proven on several production FE street engines. It can be a little time consuming to set right on a race car and it isn't as dependable on a race car at WOT consistently.

The carbs backwards also mounts the primary throttle over the heat passage in the manifold which depending on your climate is a better location for the choke to be located over.



You can see the clearance between the carb and the distributor cap in my picture and the proximity of the cap and front bowl in J.'s.

The "factory fuel log" will work with either positioning but tends to block quick access to the linkages.

Personally I use the 427 linkage.

I installed some heim joints in them for more accurate movement.

[J_Speegle]

Likely does not help with the possibility of using progressive linkage (as mentioned if the intake design will even allow this) but thought I would post a picture of at least what one team was using in 67

[TA Coupe]

This is the linkage setup that I have been running for over 40 years on the street and track. No Progressive linkage, and it has run great. See if anyone can figure out what this engine is. As I will bet that almost none of you have ever seen one before outside of Randy Gillis, Jay Cushman and maybe a few of my other friends.

[shelbydoug]

It appears to be a Boss 302 with 2 1850's and an automatic transmission.

The only manifold that I have seen for that set up is the SHELBY lettered intake but it could be another variant of that one?

The SHELBY version had a rather radically overhung rear plenum that I can't see in the pictures? This looks more like a T/A on a Boss 302.

The Shelby Boss 302 appeared to be a modified 289 T/A manifold design. There is also a Tunnel Port 302 T/A manifold and all seem to revolve around the original 289 manifold designed molds.

Notice the size of the carb bores? That's an indication of the carbs it was designed for. Those are 780 bores.

Only the builder can tell us for sure what kind of a mix this is. Lots of possibilities with manifolds and linkages.

Interesting set up though.

[Starliner]

Thanks to all.. Jeff that factory team photo looks to use the same slide bar ( black in photo)  progressive linkage, I have and Carl's Ford sells. Of course we don't know how high that race car idle was set on the carbs.. My 65 K code wont be raced to much lol.. but you never know.. ( I still wonder if the intake provides idle on single primary if best.. agreed )

Joe

[shelbydoug]

Thanks to all.. Jeff that factory team photo looks to use the same slide bar ( black in photo)  progressive linkage, I have and Carl's Ford sells. Of course we don't know how high that race car idle was set on the carbs.. My 65 K code wont be raced to much lol.. but you never know.. ( I still wonder if the intake provides idle on single primary if best.. agreed )

Joe

The T/A linkage isn't particularly friendly with a nice idle. Those cars generally idled about 1,100 on a good day. Maybe 1,400 is more like it?

As I said, the 427 linkage mounting the carbs backwards is more appropriate for a street car for a bunch of reasons.

It depends on what you call a street car?



I saw a replica of "General Lee" pulled over on the side of the road by a Trooper.

The driver was climbing out of the driver's door window since the doors were welded shut. Let's just say the cop wasn't very happy about the situation? Maybe the cop just didn't like the number 99 in the meatball on the door? Who knows? It's a free country. To each his/her own. That guy just had a lot of "splainin' to do".

The guy even had hair like John Schnieder.

The ONLY possible way that this guy was going to be let go is if Catherine Bach was there strutting around in here 'Daisy Dukes"?

[gt350hr]

    Doug Roy has cylinder heads that few know exist. They are indeed canted valve heads BUT they have 289 size ports and accept 289 / 302 intake manifolds. So Roy uses the 289 T/A intake on this "special" set of heads. To fill you in a bit , Ford want to do a "low cost" boss engine for '70 and built some prototype parts . I have the Engineering proposal paperwork . The program wasn't enough of a saving to warrant it . Some of the heads "escaped" and Roy had an engine built with them. They have conventional "style" Boss exhaust ports but are down sized a bit. Really cool and REALLY rare.
   "67,8,9" dual four manifolds all had the carbs facing forward. In the begining , the Ford linkage was used with BJ-BK carbs. Later the teams made their own versions which used "heim joints" ( or spherical rod ends) . Most used steel tubing for the "linking" between the rod ends. Mine was made by Shelby Racing Company and was one of the first to use aluminum hex stock. The next year (70) dual quads were illegal.
      Randy

[shelbydoug]

    Doug Roy has cylinder heads that few know exist. They are indeed canted valve heads BUT they have 289 size ports and accept 289 / 302 intake manifolds. So Roy uses the 289 T/A intake on this "special" set of heads. To fill you in a bit , Ford want to do a "low cost" boss engine for '70 and built some prototype parts . I have the Engineering proposal paperwork . The program wasn't enough of a saving to warrant it . Some of the heads "escaped" and Roy had an engine built with them. They have conventional "style" Boss exhaust ports but are down sized a bit. Really cool and REALLY rare.
   "67,8,9" dual four manifolds all had the carbs facing forward. In the begining , the Ford linkage was used with BJ-BK carbs. Later the teams made their own versions which used "heim joints" ( or spherical rod ends) . Most used steel tubing for the "linking" between the rod ends. Mine was made by Shelby Racing Company and was one of the first to use aluminum hex stock. The next year (70) dual quads were illegal.
      Randy

Thank you Professor Peabody and for the trip back in the  "way back machine" .  Those are ALWAYS fun with you driving and greatly appreciated by me .



I saw the indentations on the tops of the exhaust ports like the iron Boss/Clelveland heads have and of course the Shelby "Cleveland" valve covers. Other then that, I know there were a bunch of "prototype" manifolds cast up that had strange combinations and sometimes leaked out to the public. The manifold therefore was anyone's guess.

I have actually had a few of those myself.



My linkage is evolving into spherical rod ends, threaded hollow tubes (.049" wall) and hex rod as well where clearances permit. Often my posted pictures were yesterdays setup and today...well it isn't finished yet!

I think I need to go with bearings on the cross shaft? There is too much play in that.


As far as which way to put the carbs, that's optional in my view but I started with the 427 backwards, went to the T/A forward and now back to the 427 backwards.

I'm just speaking from preference there, but I have reasons for it.



I can see where the 427 stuff is marginal for racing at best. I've already locked mine up twice at WOT and had to shut the engine off to fix it. Rod ends are helping that situation and with those center squirter Holleys with the mechanical secondaries it would be just a disaster waiting to happen.



Not that I drive my car much over the winter but I do need the choke and use the automatic version.
I found in my case it is imperative to have the correct choke thermostat in there to keep the engine running until it heats up enough to do the correct kick downs.

I also need the primaries over the heat passage in the manifold. Here, you WILL literally ice the carbs in cold weather high speed running and the heat crossover passage is the only thing that will save you.



Also consider I'm talking about a street car and there were NO Trans Am street cars that I know of regardless of what year? 

The "factory" front linkage also needs a longer slot then provided so I'd need to fabricate that one. The slot in the secondary 427 needed to be elongated about 3/16" to provide for the changes that the automatic choke does to the linkage until it kicks down but there was enough material in the rod itself.

So for me, the linkage is selected for what works best for my application, not for what was "correct for a 66, 67 or 68" factory race car. 



I'm on the third pair of carbs and every time they were changed, the linkaged needed to be altered also. I was in to that so much that the "factory fuel log" was just constantly in the way which caused a change to the fuel plumbing.

Whether that stays like that remains to be seen but my air cleaner setup uses a Cobra oval air cleaner and 68 KR air ducting so when in place, the plumbing is concealed.


I'm not telling anyone what is "right" just sharing my experiences and trying to explain why I made those decisions. A T/A manifold on a street car is not going to be judged in "Concours" and for that matter, how many R models are as delivered new in details? So what's the point?

Someone here trying to make a counterfeit tribute t/a car? Really? Why?

Isn't giving technical information to counterfeiters illegal?



It would be technically interesting to see how a "factory race car" was delivered new and then how the race mechanics took stuff off, threw it over the fence at the neighbor they didn't like, then fabricated what worked for them?

From what I have been told, that's how the "works race Cobras" were, with no two exactly alike regardless of what was "correct" from the factory. 


Here's a picture. Everyone loves pictures. Sometimes I prefer Crayolas and coloring books. Again. Just a preference.

[gt350hr]

  FE's backwards , small blocks forward. The '67 Mustang engine assembly manual  ( from Osborne) shows the proposed ( never made it to production) small block setup.

    The original Ford linkage ( slotted for rear  carb) was soon replaced by the one to one linkage.
    Randy

[shelbydoug]

Mustard on hot dogs. Ketchup on burgers. Everyone knows that.

[pbf777]

     The original Ford linkage ( slotted for rear  carb) was soon replaced by the one to one linkage.
    Randy

     And this is how one should be equipped, as to have the primaries opening mechanically simultaneously, as otherwise the air/fuel charge has a torturous path to follow in order to arrive to some cylinders versus others, in part throttle instances.       

     Scott.

[shelbydoug]

     The original Ford linkage ( slotted for rear  carb) was soon replaced by the one to one linkage.
    Randy

     And this is how one should be equipped, as to have the primaries opening mechanically simultaneously, as otherwise the air/fuel charge has a torturous path to follow in order to arrive to some cylinders versus others, in part throttle instances.       

     Scott.

Makes for outstanding torque! 

[pbf777]

Makes for outstanding torque! 

      The idea of multiple inlet runner lengths presented in a singular but multiple cylinder engine is not new, and historically practiced.  Perhaps the most infamous American V8 example of contemporary automotive history, with great popularity in racing, and therefor thoroughly examined, would be the big block Chevy, 396-454's, as the induction track within the cylinder heads were originally engineered by the O.E.M. to present two different R.P.M.'s at which the peak torque sum would be acquired; this intention presenting a broader torque curve, but would be at the expense of the peak number. 

      Unfortunately, this has also proven a major shortcoming from the competition performance angle, for a number of reasons, and has intentionally been attempted to be eliminated in the aftermarket racing cylinder head arena.  Notice how the current NASCAR GM cylinder heads are of the symmetrical port (looks more like the Ford product) vs the siamese configuration which inevitably leads to an imbalance of mixture delivery whether intended or not;  and do you know how difficult it is to get a Chevy guy to relinquish their design, and adopt, if only in general appearance, the Ford design; there must be something irrefutably superior to the later.     

     Scott.

[shelbydoug]

The consideration of the compromises of the Chevy runners is completely irrelevant in comparison to the Ford 289 trans am intake.

There is no other intake like it.

The runner configuration on the Ford t/a manifold is equal length runners for WOT. That's the point of this manifold. It has little if any compromise in that respect. Anyone who puts one on the bench and examines it will see this immediately. It was designed before tunnel rams came into existence or common use or availability.

It varies from the manifold used originally on the Shely Team '69 Boss 302 t/a which is a true isolated runner manifold.

It obviously is somewhat of a hybrid in that it has provisions for choke crossover heat passage and integrated part throttle homologation like the Ford 427 street HOLLEY dual quad manifolds do but those are not equal runner manifolds. The t/a is.



There may have been configuration "proposals" for obviously limited street production but the surviving documents showing that configuration could not possibly have been tested in the dead of winter in Minnesota. It's not Arizona.  That proposal is STRICTLY for a race car, not a street car. Get real.



By comparison to the "High rise" 2x4 HOLLEY intake, the runner passages are huge. Maybe close to 100% larger by volume. Just funneling down to meet the larger GT40 intake ports of the heads with a smooth transition.

As a result there is some loss of velocity and therefore some torque loss at off idle rpm's but just like driving a car with a longer duration camshaft with a manual transmission car, you don't stay in the 1,500 rpm range for any significant time.

If you wanted to use this setup with an automatic transmission car in traffic, that's a very different story and not something that you likely would be happy with.



IF I was looking to maximize top hp then I would agree that it would run best with two mechanical secondary carbs with both carbs on a 1 to 1 ratio, both opening at the same time, BUT I'M NOT. That is all purely academic. It simply doesn't matter.



The original 289 Trans Am engines as installed in the SA coupes were dynoed at 366hp with two 660 center squirter Holleys using progressive linkage, carbs facing forward, iron GT40 heads.  What happened to that set up after being delivered to the first owners probably varied considerably just like the cam selection was.


Because of the original Ford design considerations, this manifold is a very, very good street intake.  provided you use configurations benefiting street use rather then WOT 7,000 rpm plus operation. It has the flexibility to do that...or both?


Certainly with street use on a 289, smaller vacuum secondary carbs would seem to be in order. That was suggested in the 1969 Shelby Autosport catalog listing. So far though, it looks like just about any combination that you want to run will do just fine? It's not easy to screw this thing up. That says a lot.

I'm not sure if using it with an automatic transmission is a good application? I don't see major issues with a manual transmission though. Go for it. You won't be disappointed.


"taste great!...less filling!" Do we need to argue? It's both.