270 welch plug size

[motto]

I always instal brass plugs if I can get them.
You mention failure of the rear plug as being a real inconvenience Phil. I once loaned my Chev 4403 1-1/2 ton 4x2 to a friend so as he could haul a WC51 a thousand miles home. The night before he was to begin the return trip. Water on the floor!!!!
He rapidly identified the source as being THAT plug, managed to locate a replacement and spent the night removing and re-installing the gear box, flywheel and bell housing. Fortunately he could do it that way as to remove the engine from the truck meant removing the front clip or trying to tilt the engine near vertical.

David

[Richard Farrant]

Welch plug is the term for the dished plugs with ground edge, the others are cup plugs.
They have nothing to do with releasing pressure if the block freezes, just part of the process of casting blocks. Some engines have screwed plugs.

[harrygrey382]

Thanks guys. It's actually for my uncles GMC he just acquired off a family member. He's just started it but found the welch plugs were missing. He's bunged them up with big tapered corks just to run it but wasn't sure what size to buy. I'm sure he'll get brass ones... Runs well considering how long it's been sitting!