Re: Henry's 37 Limousine

Posted by Ross On 2017/4/26 17:43:32

The heads with the 10 mm plugs have much less meat in the thread area. If you drill and tap and re-spotface to accommodate 14 mm you will have very little thread engagement. I do not recommend it.

A crack on the top side of the head is inconsequential. Put a little stop leak in it and just drive it. A crack on the top of the head has nothing to do with the combustion chamber.

If you really want to use the other head, leave the helicoil alone. In aerospace practice EVERY tapped hole is helicoiled.
Do a simple truing up cut on the head and slap it on. Are you going to loose sleep at night wondering if you could have had 3 more horsepower?