Identifying KF cylinder heads

[Fid]

Here's a nice looking one on ebay.
http://www.ebay.com/itm/1949-1950-1951-1952-1953-1954-KAISER-SUPER-SONIC-CYLINDER-HEAD-/220961081748?pt=Vintage_Car_Truck_Parts_Accessories&vxp=mtr&hash=item33724e8994

My question is this - KF had at least two different heads used. There was a higher compression head for the Frazer Manhattans and possibly some of 1949/50 Kaiser deluxe (color) models. I believe it was also an option on the '47/'48 Customs as well and perhaps some of the post '51 Kaisers. Is there a way to tell them apart? This seller likely doesn't know there were different compression ratio heads. Does anyone know how to tell them apart?

[joefrazer]

The pictured head is for the 51-53 cars, also the 54 early Specials. The 54-5 head has '226' cast in place of the Supersonic lettering. Earlier heads differ in that the casting ribs are fewer and the Kaiser and Supersonic aren't cast. My early 47K has 6.86 cast into it denoting that it is a 6.86-1 (instead of 7.3) compression ratio head.

[Fid]

That's cool, then they are distinguishable (if that's a word). I may be mistaken regarding the cars the higher compression head was used on. I just looked in my copy of the 1947/48 KF Parts manual and it does not list a higher compression head. It lists one for "all models" and one used on Right Hand Drive cars which I thought was interesing. Perhaps the higher compression head was available begining with the 1949 models. I don't have a '49/'50 KF parts manual. I'll check the handbook.

[pnw_oldmags]

But Fid they are online for you.

This is the 1949 page
http://circlekf.com/kflit/PM/kfpm460/kfpm460010.jpg

[kaiserfrazerlibrary]

Kaiser-Frazer issued a Service Bulletin about the 7.3:1 compression heads during the 1947 model year.  Frazers (all)  and Kaiser Customs would be the first to get the higher compression heads, with kaiser specials getting them as production increased.  Plan was to reserve the 6.86:1 for export cars and all domestics would be 7.3:1 heads. 

[Fid]

Thanks for the reminder Jim, and thanks for the response Jack.  I was pretty sure, but didn't want to say till I had some evidence, that the '48 Custom that I've mentioned on here several times,  had the higher compression head. This confirms it. Perhaps my copy of the parts manual was an early issue? It only lists the one head with one number. I also recall the '49 Frazer Manhattan we had had the higher compression head and the dual throat (2 barrel) carburettor which boosted the 226 CID engine to a whopping 112 hp... if I remember correctly.  Good info gentleman.

[kaiserfrazerlibrary]

All dual-manifold engines have the 7.3:1 head.  Also, FYI, the next release of KFOCI HANDBOOK (5.0, release date unknown) will have copies of "timeline significant" Service Bulletins and other factory documents that establish when significant changes were made to cars in production (new heads, start of 1948 model year production, switch in spark plugs, engines built with back-up crankshafts & serial numbers for same, etc).

[Gordie]

Thanks Jack,  that will be great info for us to have.