Freeze plugs ?

Hi crew,

got a question about freeze plugs for LA318 und Magnum 318 engine blocks.
I have 4 different 318 blocks at the shop right now (3x LA, 1x Magnum). 3 out of these 4 blocks use 1 5/8" freeze plugs for the openings on the back side of the block (trans side). One of the LA blocks I have has larger holes in this area, I would assume 1 11/16" (measured 1.687" with calipers).
So whats the deal? Did Ma Mopar use different size freeze plugs through the years or did someone tinker with the holes somewhen down the road?
If the larger bore size is stock, what would be the correct freeze plug size? What engines use that size (I have trouble sourcing the plugs in Germany by size, usually the parts are listed according to the application).

Thanks,
Frank

Hey Frank

What's the year of the block in question?

The block is from 1970.
http://www.moparpics.com/gallery/view_photo.php?full=1&set_albumName=album666&id=IMG_0380

I am currently building a 360 Magnum and I had to buy two sets of freeze plugs because there were too many of one size and not enough of the other. It sounds like the same issue. The sets I bought were supposed to be correct according to Hughes Engines but there is a difference.