Trans Am Intake Port Sizes

[shelbydoug]

What is the difference between the  C60A and C6ZZ 2x4 Ford T/A manifold?

Is it the port size? I have the C60A but don't have the other to compare it to?

How does the SHELBY labelled version compare? 


The pictures of the C6ZZ on the Mustangtek.com web page appear larger but that may be a ported manifold.

The ports on the SHELBY manifold are not shown.

[gt350hr]

   "Port" wise , they are all the same and all perform the same. I have tested all of them including the SK part numbered version. The C6ZZ number was done specifically to satisfy the SCCA.

[shelbydoug]

I just used Mr.Gasket 302 intake gaskets. They fit my AFR 1388 heads perfectly.

When layed up against the intake manifold, the ports on the intake are both narrower and shorter.

Is this by design?

The 302 and 289 Ford head port openings are the same. The 351W is a little bigger resembling the GT40 head ports but not exactly the same. Similar.


Don't be afraid. There is no way that I am going to port match the intake to the heads. 

I had a Blue Thunder 2x4. The ports as cast were similar to this T/A.
That one I did port match to the heads but those were 302 iron heads at that time.

THAT is a VERY torquey set up off of idle.



Where is this cylinder #9 that the C6ZZ firing order refers to? 

[gt350shelb]

hard to find that nos #9 PLUG WIRE!

[1109RWHP]

What does that even mean?

[shelbydoug]

What does that even mean?

The firing order on the C6ZZ manifold has no number 8. Instead it has a #9. 

[TOBKOB]

What does that even mean?

The firing order on the C6ZZ manifold has no number 8. Instead it has a #9. 

Maybe that is to prevent crossfire between cylinders 7 & 8...     

[shelbydoug]

Well, according to Randy, the C6ZZ manifold was cast specifically to satisfy SCCA requirements.

I find it peculiar that with the mistake in the firing order, the manifold was sanctioned? 

The C60A was already being run at least on the Shelby T/A cars, so what was the big deal to the SCCA?

It's always the pencil necks who make the "issues". 

[gt350hr]

    Doug I have had two C6ZZ intakes from genuine SAI built '67 T/A engines. They are serial #9 ( which I still have) and #31 that was on the complete engine #31 I got with my Hertz car. Dan case also has one with a serial # on it.There are two unsubstantiated rumors regarding the #9 that I won't comment on. Popular opinion is it was a mistake at Buddy Barr.  I haven't seen a C6OA or SK version with an SAI engine number on it. I certainly haven't seen them all.

[shelbydoug]

    Doug I have had two C6ZZ intakes from genuine SAI built '67 T/A engines. They are serial #9 ( which I still have) and #31 that was on the complete engine #31 I got with my Hertz car. Dan case also has one with a serial # on it.There are two unsubstantiated rumors regarding the #9 that I won't comment on. Popular opinion is it was a mistake at Buddy Barr.  I haven't seen a C6OA or SK version with an SAI engine number on it. I certainly haven't seen them all.

What intake was on the 66 Shelby coupes? Were those single 4's?

If a part needs to be "homologated" with the SCCA, why does it matter which part number? It's the same manifold isn't it? Why did Ford need to change the number?

I know that a disproportionate amount of paper pushers seem brain damaged but I'm missing the justification of two different part numbers considering Ford's method of renumbering them even with slight changes from the previous design.

These are not arguments by me. Just questions needing clarification in a world of confusion.


Were the intake ports on your two SA assembled versions port matched or left as cast?

[pbf777]

    I haven't seen a C6OA or SK version with an SAI engine number on it. I certainly haven't seen them all.

     One of the intakes we have here is #17, it has the "FIRING ORDER" but no other casting identifier; and I have looked closely, and am not able to establish that such may have been removed.     
                                                                                          15426378

    Scott.

[gt350hr]

    '66 was single four. Ported COBRA. For '67 dual fours were allowed. The early dual four was a turd so a new version was designed. I can't answer the reason why changes to the castings were made without looking at the blueprint itself as the original design engineer of that intake has passed.  Maybe I misled you in saying the part number was changed for the SCCA. The SCCA did "suggest" a Mustang based part number , and a "revision request" ( some minor change to the casting or machining of it) allowed the C6ZZ to be assigned to it. You are correct that the part (casting) number could only change due to a revision. You will also note that Z as the last letter is uncommon for a casting number.  A and E are the most common suffixes used in cast engine parts.The C6OA was distributed in many of the over the 2 4V induction kits which were very popular at the time.
      Both of my manifolds had "smoothed" entries , not port matched. "I" port matched #9 to my VicJr heads and saw NO improvement on the ET slip.

[shelbydoug]

    '66 was single four. Ported COBRA. For '67 dual fours were allowed. The early dual four was a turd so a new version was designed. I can't answer the reason why changes to the castings were made without looking at the blueprint itself as the original design engineer of that intake has passed.  Maybe I misled you in saying the part number was changed for the SCCA. The SCCA did "suggest" a Mustang based part number , and a "revision request" ( some minor change to the casting or machining of it) allowed the C6ZZ to be assigned to it. You are correct that the part (casting) number could only change due to a revision. You will also note that Z as the last letter is uncommon for a casting number.  A and E are the most common suffixes used in cast engine parts.The C6OA was distributed in many of the over the 2 4V induction kits which were very popular at the time.
      Both of my manifolds had "smoothed" entries , not port matched. "I" port matched #9 to my VicJr heads and saw NO improvement on the ET slip.

What was the "turd" manifold?

I thought I had a T/A manifold in the C60A? I'll need to stop referring to it as that. It's not. 

The implication is to leave the ports alone as cast. What does the intake port look like on the GT40 head? It's too bad that cameras didn't exist back in the day in the SA Race Shop. Maybe they did and the mechanics kept breaking and throwing them around?

The lack of documentation from it is surprising. Was the information too proprietary?

[427heaven]

I believe that is a reference to the original COBRA dual quad set up with the little letters on it. I know my cars feel a little racier with the 2 fours on it! Maybe its all in the coolness factor, it takes me back to the early 60s

[shelbydoug]

I believe that is a reference to the original COBRA dual quad set up with the little letters on it. I know my cars feel a little racier with the 2 fours on it! Maybe its all in the coolness factor, it takes me back to the early 60s

Do you mean this one for the dual Carters?