Geez Craig.....I said to ignore it, actually these were a swap meet purchase years ago, don't know any history, but agree they are pretty bad! They contributed their balance tube fitting pieces to fix another set which was without fittings.

Sorry Alan, I didn't mean to make it sound like I was blaming you personally for it.

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James,
Years ago at the Pellow auction they were selling A/B heads by the pallet load. I ended up buying one of the pallet loads because I noticed a 2-pc case head in the mix which I wanted. The rest of the heads got stacked in the back of the storage shed. I decided to look at them and see if I could answer your question. If by "fin" you mean that the casting around the guide is slightly smaller and comes to a fairly sharp line on the inlet side, the fin was only present in 2 of the 13 heads. I have one with the "fin" dated, I believe, the 12th week of 1955 which was not a split head and one with the "fin" dated the 43rd week of 1956 which was a split head. The rest which were dated, as best I could tell, from the 25th week of 1957 to the 8th month of 1960 did not have the fin and were not split. Some had no dates or the casting mark with the date was not legible. Most did not have a maker id although a couple were apparently cast by Kolbenschmidt and except for the 1960 head all had no part number although they did have casting marks of 101/x where x was either 4, 7 or 8 which may have reflected drawing changes or pattern identification or casting vendor or nothing. I suspect the fin you are talking about is probably date related and nothing else.

Thanks Alan, that's some good info! All those dates agree with everything I have too.

I'm attaching a photo of the "fin" below. The 528, 528/2 and early 616/2 heads (with the split) were like this. The 546 and 546/2 heads were not. Not sure about 616/1.

Those 101 1 and 101 2 are the Karl Schmidt "Kolbenschmidt" part numbers. They refer to versions of the Porsche heads. The earlier the number, the earlier the head. "101 1", "101 2" and "101 3" are all pre-A heads. The 1954 and 1955 heads were the same castings, just different machining to give different bolt spacing and different spigot size for the cylinders.

The "101 4" heads are the split 1956 616/2 heads.

The interesting thing about the fin is that, for instance, KS "101 2" heads from 1953 and 1954 have the fin in the oval port version for the 40 PBIC manifolds, but do not have the fin in the circular port version for the 32 PBI manifolds.

Here's the typical ports on heads with manifolds for the 32 PBI carbs - 506, 546 and 546/2 engines. These ones are early. Probably 1951-52.

And Alan, notice the shape of the bottom of the earliest version of the 32 PBI manifold (with the lousy porting) matches the shape of attachment point of these heads. So yeah, those are the earliest ones. Agree with your assessment. These are 101 1 heads.

Finally, here's a set of 546/2 heads from early 1955. Round ports, no fin, and their original manifolds for the 32 PBI carbs are the 3rd type you show Alan, the ones with the balance channel between the ports.