Mystery hole question

[tpj71mach]

I am new to Ford engines and am wondering what these holes in the 4V closed chamber cylinder heads are. I noticed them when the engine came back from the builder. The engine was broken in and dyno tested so they don't seem to affect drivability. I can't see too far down them and I loaned my boroscope to a buddy last week so I can't see how deep they are or where they lead. Any info would be appreciated, at this point I am assuming they are nothing to worry about but just thought I would ask. Thanks

 

[Steve McMahan]

I guess there are several theories of the purpose of this hole(s). I remember asking about it at the Ford dealership I worked at one summer. One mechanic told me it was used as a locator point in machining the heads, and another told me in an older engine design, it was used to route air to a riser for the choke system, long replaced, but the initial bores hole remained. IDK if any of those are true, but there you go.

 

[Spike Morelli]

That hole is machined into the casting for a machining tooling locator pin, at the factory. after machining, it has no purpose. You will find two holes machined, one at either end of the pan rail, on the underside of your block as well. They locate the casting as it is machined.

 

[tpj71mach]

Thanks for the info, I assumed it couldn't be too important because the engine ran with them exposed like that.

 

[73inNH]

Ford's attempt at weight reduction. Mystery holes.

 

[jscott]

It is actually a blank hole to make you worry!! When you drop a screw it will get into that hole, hide and will make you think you dropped in into the engine itself!!

 

[1973 Mach-1]

I have found those holes to be a great place in which to lose choke screws!