Reply To: 840A head

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Hi Derek,

1934 and 1935 (including 836A) used small spark plugs in cast iron heads. 1933 and earlier used large plugs.

Here is some other info to help identify heads:

1933 (and all later except possibly an 836A) had a tapped hole in the left side of the head, about 15" from front, to mount the oil cooler.
1932 and earlier did not have this hole.

1929 (only) had 2 holes to mount the oil filter on the left side near the front.

1929 thru 1935 had a raised water outlet, about 1.75" above the top surface, 1936-38 aluminum heads did not, so they look quite different.

All heads had a number stamped on the flange surface of the water outlet, but over the years they get machined or rusted off. The correct number for your car is #6 (140hp).

A 1933 head (and ’34-’35 836A) will give a little more hp on your engine (145), a 1936 the most (150), ’29-’32 a little less (132-135).

If the crack is at the base of the water outlet (typical) or some other non-critical area, it can be loc-stitched with threaded tapered interlocking plugs. I ran my ’33 for years with this type of repair.

Welding is a tricky business, but some can do it, raising and lowering the temp of the whole head slowly over a day each way.

Hope this helps.

Bob Jacobsen