567 appears to be a high-temp version.  http://au.iloctite.com/en/loctite-545-554-5451-565-561-567-5770-thread-sealing

From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of larry.eversmeyer@faa.gov
Sent: Friday, May 25, 2012 6:59 AM
To: lml@lancaironline.net
Subject: [LML] loctite

I've been reading the threads using different  lubricant on fittings.  I've read where loctite 567 & 565 are being used.  Does anyone know the difference / or  advantages between these two.

Legacy still building
Larry Eversmeyer