bought a 61 -394 that was rebuilt in 1995 ( by an engine rebuilding company) and has sat untouched ever since. Sent it to my engine shop for a complete teardown- cleanup and reassemble. Here's the question- He found that the front 2 freeze plugs{one on each side} under the heads had a 1/4" hole drilled in them so he did likewise! Question is - Why re they drilled out in the first place??? Makes no sense to me so I stopped the reassembly until I can come up with the answer. Any help would be appreciated THANKS -JOHN

 

The only plugs that should have holes in them that I'm aware of are the galley plugs to allow oil to the distributor. No rime or reason to have holes in plugs that are made to seal up the block. Have you seen the holes?...Tedd

 

The hole are to allow for a better flow in the cooling system, it helps the heads run cooler, I have done this to a couple of my engines, if you check the head gaskets you will see that the drilled hole lines up with the water passage in the heads. I found that when I tore down one engine the frost plug had rotted out there and this engine run nice and the water jacket was cleaner in the block.
I'm running 394's from 62 and 63
Steve

 

Thanks for the quick reply and help. Some others have also told me that the holes allow for better head cooling so I guess we'll just leave well enough alone! As for the oil plug holes it seems that also is correct so thanks to all -John