[bobcowan]

It depends on where the dipstick is.

If it's in the side of the block, just clean it out good, use some silicone sealant, and bolt the top tab to the header bolt.

OTOH, if it's in the alum fron t cover, it could be more difficult. The hole in the alum tends wear in odd shapes over time. Getting it to sdeal with simple silicone could be difficult. There I would try JB Weld.

If the front cover is off the engine, drill and tap NPT threads, then use a Lokar screw in type. That will fit easily, and be leak proof for years.