P23 engine head

[Dennis]

I had a 1940 Dodge business coupe in my garage, in New Jersey, for over 40 years.  I recently shipped it to my son in San Diego.  The car has a P23 engine.  He was able to get it running but noticed water in the oil.  He pulled the head and noticed corrosion around the bolt holes.  I have a head from a 40 Dodge engine.  Could he use that as a replacement?  Would any 218 head work?

[Young Ed]

The p23 should be internal bypass and that 1940 head would be external. I believe you could use it as long as you installed a plug in the water hole in the block. Might be easier to find the other type of head. 

[dpollo]

Yes, it will work but as noted above there is an extra water passage in the block which can be easily plugged in one of two ways.

 Tap the hole 9/16 NF and make a threaded plug from a wheel bolt   of the same size.... cut and cross-cut a screwdriver slot in the bolt stub.

  Or :  remove the water pump  and make up a gasket which blocks the hole behind the pump.

[greg g]

Some of the head bolts go into the coolant passages.  They need sealer on the threads to keep the coolant where it belongs. These are for chevy small block, but are just the thing for the flathead.  Come with coated threads.  The part number includes 25 as this is the count per box, only actually need 21.  Got them for about a buck a piece but that was, in 2006.

Edited September 18, 2017 by greg g

[Veemoney]

I have not seen the head but a little corrosion on the head is not unusual. Couple suggestions:

1. Inspect the gasket to determine where the leaking occurred. the narrow sections fail sometimes
2. Check the head that was pulled off to see if it is flat.
3. Milling the head to clean up some of the corrosion can be done and will raise the compression giving you some added power. Most automotive machine shops can do it. Some threads on here to measure the thickness of your head to determine any milling previously done.

[Dennis]

Thanks for the suggestions.  I just inspected the head from the '40 and it appears the spark plug broke in the #6 cylinder.  The threads are bad.  Rather than tap it and use a heli-coil we'll look for a replacement head.

Thanks for the tip on the head bolts.  They are still available.

This is a great site.  Wish I had found it sooner.