Gel like substance in water neck?

[drfromnc]

I drained the water from my flathead so I could add small piece of SS pipe on top of thermostats to hold them in place and noticed some globs of gel like substance inside the water necks of each head (Vintage Edelbrock aluminum heads).

This motor was built 2.5 years ago and I have only started it up 2 since bringing it home. It’s only had distilled water in it. Also noticed a bunch of small whitish colored particles on the ground underneath truck that came out with the water. See pics.

Well I’ll add photos when the site will let me.