Help identifying twin plug heads

Breaking down a '72 MFI motor that was poked out to 2.9. I have a question about the heads.

date stamped 11-71 the # on them is 911-104-302-OR. I believe them to be 1972 E heads that have had the exhaust enlarged to S spec and a twin plug machining at some point in their lives.

Intake and exhaust measure 32 and 35

Valve size is roughly 40mm and 45mm

I will have to clean them and make a proper measure in MM with a proper tool. Looking through BA's handbook and I don't see any production heads with these measurements.

They are twin plug with the smaller plugs on the bottoms.

Any help?

Twin plug heads are almost invariably custom machined for twin plugs. Factory twin plug heads...well, they don't exist among mere mortals. By the head numbers, these are 1972 'T' heads:

http://www.early911sregistry.org/for...ead.php?t=9481

Hard to think in decimal inch

1.25" 31.75mm

1.375=34.925

I assume those are the ports?

Hello: I have owned 2 sets of factory early twin plugged heads. The first was a well raced set of 2.5L ST heads. These had very large cast in ports. The second set was a set from a 2.8 RSR. I wish I had that set back so I could sell them again right now ;-). They had even larger cast in ports. The reason I sold the heads is that you can port heads to flow better than the original factory heads of that era. The factory heads also take the smaller spark plugs that are 12mm instead of 14mm. The "T" carb heads make a great head to modify. They have more material where it is needed for good flow. They are also good to modify for MFI since you can change the injector angle. Thanks, Eric

It sounded like your heads had two different size spark plug holes, a big and a small? Factory duel plug heads have two small plug holes.

Indeed they do have the smaller 12mm plug on the bottom. Definately not factory race heads, but they would give someone a head start on a project motor with the machine work already being done. Thanks for all the input.

I was under the impression that for all heads of that age the exhaust valve size and port size were the same for T E and S heads. The inlet valve sizes were again all the same for T, E and S heads but the inlet port was differant I think 30mm for T 32mm for E and 36mm for S heads.

HTH

Regards

Well whatever these are......I have them posted for sale on pelican for $1600 for the whole set. Heads,cam housings,cams,rockers etc.