so far my favorite is the mr gasket for a big block mopar, the last couple have been mostly swing free and get up to temp way faster then any other i have tried. i installed the rear freeze plug bypass kit when i had the head off a couple months ago and i get a little swing now but before hardly any, the cummins t-stat i got after i bought the truck had the gauge swinging like a windshield wiper and took forever to warm up