Hot Rods Freeze plugs in cylinder heads

Gentlemen,

I have a late 70s small block Ford (302/5.0L) that I am preparing for a future project. While the engine is out I plan to replace the freeze plugs/soft plugs/expansion plugs. I have looked at the "kits" from Melling (MPE-108BR), Milodon (MIL-34035), and Summit's G1583. These kits include all the plugs for the block but not replacement plugs for the front and back of each cylinder head.
Do they know something I do not know? I know I can remove the plugs out of the heads and take them to NAPA to be matched up, but I would like to know what y'all do? Do you just change out the plugs in the block and let the heads go ?
Many Thanks !

 

They all rust.... change them.

 

They are sold by diameter. Just measured the hole.

These are not for anything mentioned.

They exist for cleaning out sand from the casting process.

 

I'd change them, easier now than later....

 

Dorman catalog says 555-077, 1-1/2" diameter

 

As a former engine rebuilder the head plugs were never offered in any kit that I used. As squirrel said there 1-1/2 and need to be replaced just like the ones in the block. We used to buy them in bulk and always replace them when doing valve jobs.

 

I bought a kit off Rock Auto that had all of them, block and heads both.

https://www.rockauto.com/en/moreinfo.php?pk=8311428&cc=1133525&pt=5332&jsn=553

 

Many thanks to all the replies. As luck would have it, I did order a Melling set from Rock Auto. So it looks like I am covered. Dorman would have been my next route, so thanks Jim for the Dorman detail. Great website ! Always sound advice.

 

I never bothered changing them and so far have been lucky.

The plugs I have had fail were on installed engines, and they were the ones right up against the motor mounts, of course.

 

On the Mopar engines,,,it seems the head plugs hold up better than the ones in the block .
I’ve never had any fail,,,,,,but,,I have removed some that were border line,,,,right on the edge of failing .
And,,,,,most are 40-50 years old now,,,,maybe older,,, depending on the core to rebuild .
I always remove them to aid in cleaning the inner core area,,,to aid in removing scale and such .
Better to be safe than sorry,,,,,they are fairly cheap at a parts store,,,,Dorman carries all the sizes .

Tommy

 

I had to pull a head on a 383 to replace a plug once....yeah, they'll all fail if the cooling system isn't maintained.