Any body here use the silicone "clear white" pushrod tube seals?

I'm getting ready to pull my engine out of the Hooptie (my 66) to reseal it up. It's leaking from a couple of tubes, under the barrels, the sump plate. This is the FREE 1776 that I got a couple years ago. The guy who built it used some very nice parts and did a nice job building it. However, the sealant he used wasn't up to the task. I'm thinking about trying these seals out.
Has anybody hear used them before? What do you normally use?
Scott Faivre