Would think normal expansion & contraction of a freeze plug would foil this over time.

i would machine the plug - at least try......send me a few

Thanks for the offer Eddie!

I wasn't able to locate a new or suitable mint used expansion plug (1 1/4", steel, unplated, unstamped) so I contacted a small freeze plug stamping company who did a custom run for me. I have several.

New intake expansion plug stamping, 1 1/4" unplated steel, no mfg markings:
https://farm5.staticflickr.com/4283/...9dc8ca8b_c.jpg

New Stamping vs Jobber zinc plated plug
https://farm5.staticflickr.com/4284/...97f2766c_c.jpg

Reverse side of factory original 472 manifold with expansion plug (unplated steel)
https://farm5.staticflickr.com/4262/...722613f9_c.jpg

They look great.

Well done. Now you can sell the extra plugs to the shop that restored your intake.


Jason

Installed.

https://farm5.staticflickr.com/4295/...732f6032_b.jpg

nice job!

So... you gonna offer some of your extras for sale on this site?

x2