That's why the short bolt.

   God Bless.   Tim                           http://yblockguy.com/

350ci Y-Block FED "Elwood", 301ci Y-Block Unibody LSR "Jake", 312ci Y-Block '58 F-100, 338ci Y-Block powered Model A Tudor

tim@yblockguy.com  Visalia, California    Just west of the Sequoias

The plug itself seems fine however the bolt hole goes right though to the pushrod passage ..mmm ..



"Came too close to dying to stop living now!"

Sometimes called "Expansion plugs"  although in an expanding situation the block is usually what pops out.

   God Bless.   Tim                           http://yblockguy.com/

350ci Y-Block FED "Elwood", 301ci Y-Block Unibody LSR "Jake", 312ci Y-Block '58 F-100, 338ci Y-Block powered Model A Tudor

tim@yblockguy.com  Visalia, California    Just west of the Sequoias

Ahh mee no speka engrish... Welsh plug.. hahaha yes R/H/S rear filled with crud



"Came too close to dying to stop living now!"

"Freeze Plugs" fill the openings in the cast iron engine block and heads where the foundry originally removed the core sand from the casting's water galleries. By boring the holes smooth and fitting them with stamped tin plugs the block is sealed back up to be "water tight" (sometimes). The tin plugs usually rust away in later years and make a mess - the best policy when rebuilding is to use brass plugs (of the right size) when you can find them.

Besides the freeze plug at the rear of the right head, nearby there is a tapped hole into the head water jacket that must be sealed up. I have filled them with a short socket head set screw and hard setting sealent to leave the surface near flush. 

 
 Steve Metzger       Tucson, Arizona

We call them "welch plugs", i assume you are referring to rear one on RH cyl head behind intake? you can use 23 mm brass plug from most parts shops.

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

After trying to clean up my heads as much as possible after what I thought was a disaster [much thanks to Rick for coming and helping me save the ol' girl] I discovered that "hole" on the passenger side head.. .. big hole.. so whats a freeze plug??



"Came too close to dying to stop living now!"

i bought a set of used heads and when i got them home i saw they were not a match.somewhere along the line they changed one head and put on one from the opposite side.they put the freeze plug in the back as you couldnt miss it but left the one in the front in place.the intake covered it over and they ran it like that.must have been the hottest rig in town.

I think Charlie has nailed it.  The heads have been switched side for side, therefore the water passages in the front will have one severely restricted and one blocked entirely.  Better pull the intake and verify it before going any farther.

John - "The Hoosier Hurricane"

Didn't see it mentioned but if you use too long of bolts in the threaded holes you will bend a couple of push rods. Like Duck mentioned, use SHORT bolts.



By the way, Welcome to the Site...

BOB