what to do with this hole in eng block
 

So I have a 400 motor that I just rebuilt. And I noticed this hole after it came back from getting vatted out.

https://cimg0.ibsrv.net/gimg/www.for...9c1c968cfd.jpg
I forgot about it until after I put it all back together.

I believe its for a oil dipstick. But I have one that comes out of the pan.

So How do I seal this off so I dont have leak?

Wonder if anyone makes like a really small frost plug that would fit that.

I'd say keep it simple. Get a junkyard dipstick tube, clean it up, pinch/cut it off a few inches above the rubber plug and paint it. BOOM! Done. If anybody bends over far enough to see it, kick 'em in the rear. LOL

If I recall correctly it is a 0.375 hole and a soft metal (brass) or deep 3/8" freeze plug will block it off.
freezeplugfactory.com

Yes, they do. I'm not sure of the size but I believe its 3/8" diameter.

That is the hole for the front dipstick when a front sump oil pan is used. From the factory, the hole was plugged with a small cup plug (frost plug) when a rear sump oil pan was used (4WD truck applications). A cup plug is the right fix, should be cheap & easy to find.

This plug has been on other posts on this site before. Some members had the right dimensions if you wanted to buy from a chain store and I believe Number Dummy may have also provided the Ford part number if you wanted to buy it from Ford.

When you say Frost plug assume you are talking soft freeze plug?

I thought about dropping a short bolt with a bigger head and silicone it.

Depending what part of the country you live frost plug and freeze plug are one and the same.

Thank you , I kind of thought so , but just wanted to make sure :-X21

update thank you all for the help. I finally found a 3/8 freeze plug. Got it in and place rvt sealer over the top of it just to make sure no leaks.