I was just browsing the cylinder head tech article and got blindsided by this:
Intake/Exhaust manifold bolt pattern
The 1971-1973 A12 differs from the A13/A14/A15 and most A12s after 1973 except wagons.

Scared the crap out of me because on first reading it seemed to say that the manifolds were not interchangeable between original 1200 A12's and later A-series. BUT, then I saw this right above in the same article:
Intake Manifolds
All A-series heads will interchange with either type of intake with the following caveats:
Those caveats being the coolant ports etc. I was aware of those differences already.


Heres the pic illustrating the differences

So whats the story? I want to use an old Canon manifold for Weber DCOE (designed for 1200 A12) on a later round-port A14 head. I want to combine it with a purpose-built aftermarket header, also for A12. Is this going to be a bolt-on? I can fabricate anything I need to - but I did not realize there was a bolt pattern difference.

Any experience here?

Thanks all!

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what do you call a header?

as in 4-2-1 extractors?

the weber cannon manifold will fit on the A14 head if it is an oval port manifold.

as far as i can understand the later model A12 heads and A14 heads have the manifold stud pattern (from what you've posted up) so you shouldn't have any problems...

The thing that will trip you up trying to put an early intake on a later head it the center bolt hole. The later heads have 4 studs for mounting the intake manifold, outboard of each pair of intake ports. The early heads have 2 mounting studs that are between the pairs of intake ports. This is seen in the picture you have referenced.

To use an early manifold on a late head you need to drill and tap the mounting stud holes between the intake ports to mount the manifold. Also, you may need to plug the coolant passages that are in the side of the head if the Cannon manifold does not cover them.

Gary

But then again I have a 77 A14 head that has the center holes driled and tapped from the factory.

Which would suit your application. Are they all like this?

I've seen those heads also. I'm not sure what determined if the heads got the center hole for the old style manifold.

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Yes, sorry - wasn't thinking about who would be reading.

header = extractor

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It was very late, but I remember reading something last night while I was researching about the later round-port A12A and A14 heads having the old-style 1200 A12 bolt pattern. If this is the case, then this is the head I want. Is your head a later model round-port? If so, is it the one with the casting codes front 454 and rear 990 or something different?

Ideally I would like the round port high swirl head as described on the cylinder head wiki page. The casting code info is not there yet for this head, the 454/990 head is the regular round-port. This high-swirl head is the one with the unobstructed intake ports which are "lowered to cause the charge to swirl as it enters the chamber". I am after low-mid range pull and fuel economy.