I use Hex-a-just on every engine i have build for the last 10 yrs. that doesn't have a belt drive and the only probem i've had was the excentic bushing cracked on one big block setup. The tech at Cloyes told me they had batch of bushings that were heat treated bad, and sent me 2 replacements, overnite USPS no charge. The only thing he ask me too do was email him a pic of the cracked bushing to show the mechine shop forman. I emailed the pic. on wensday about 3:00pm, got the new ones in thursdays mail. I have replaced chains after a couple hundred runs, Jegs. stocks them.
I do use the small O.D. lock washers on the allen head screws that fit in the machined out c'bored slots, so i haven't had any come loose that i know of.
Zip.