I have a head that I just pulled from a 3.8 that based on the numbers is from a S-Type. It is 7B54293-9. Based on what I have been reading, this should be a B head. The piece that is throwing me a little on it is that it has very prominently cast on the top of the head in the center between the spark plugs a large A cast into the head. Is that normal? Do B heads have a big A cast in them as well? The head also has a large amount of gold paint showing through as well so that is also throwing me a little. Thanks in advance.
You are correct that 7B54293 comes from a 3.8 S-type, the engine numbers having begun at 7B50001.
By any chance do you find a number C.26201 on the bottom?
This head casting number was also used on 3.4 MkII and 3.4 S-type.
When we speak of an A head, we mean the earliest 1949-54 standard version, which was not painted at all and did not have a letter A. It was only given that name after the C (for competition) and B head were produced.
Underneath the lettering is a little hard to read. Looks to read 114 4 w351 c14950 however the last number is very hard to make out. It then also has a stamp of V5 T3 on it. On the top then there is also a hu207 stamping at the opposite end from where the 76B is stamped. I know this came from the 3.8 as it was mated to the 3.8 bottom end of the same number. I am going to use this as a basis for my e-type motor (unless I stumble on a reasonably priced E block) so I will be sourcing a straight port head for it.
What is the large A on this head in reference to? Thanks as always for all the great help.
Perhaps I was premature in assuming the part number in the S-type book would be the same as that cast into the head.
C.14956 is the part number of the head on later 3.4 Mk1 and 3.4 XK150.
C.14958 is the part number of the head on 3.8 XK150.
C.14957 is the part number of the head on late 3.4 XK150S and all 3.8 XK150S.
If HU207 is stamped at the rear end, we believe it to be a sequential production number issued by the foundry that made the head. When we have collected a lot more of these we may be able to make a guess as to the month and year it was made.
Rob,
The HU207 number stamped at rear of head is believed to be actually added by Jaguar and not the supplying foundry.
I refer to it as a HEAD SEQUENCE NUMBER as it seems to be in numeric order of introduced Head castings being machined up and assembled into completed heads, before being allocated to an Engine build, and thus before the allocated Engine Number is stamped in.
The CASTING SEQUENCE NUMBER, is only used by one foundry, and is actually cast-in, on the underside of the head casting.
But you are right - a lot more to yet be learnt about these two numbers, with most effort to day being with respect to A-type and C-type heads from the 1950s, and not so much B-type and Straight-Port heads from the late-1950s/1960s