[BoxxerSix]

Permatex Anerobic flange sealer works very well in this application. It's a thick translucent red compound that cures to a non-hardening bond in the absense of air. Has a slower cure time than your typical threebond as well so you have more than ample time to position and torque the case halves together. I use the stuff on all gasket-less metal to metal sealing surfaces(except things like heads or exhaust components). I consistently use it on transmission or gearbox rebuilds that will see extreme oil temperatures at the seal.

I got real tired of feeling rushed to assemble a motor or gearbox once the sealant was on. With this stuff you can lay down the compound, go walk away for a 3 hour lunch, and return to your work to find the sealant still uncured and ready for assembly. Not that I would do that, but nice to know that your speedy-ness in assembly ins't so rush rush.

Just run an 1/8" bead of it and when the halves torque the compound "wets out" evenly and completely. After ~2 hours you can go ahead and wipe down any residual creep that squeezed past the seam.

Great thing too is it's readily available at just about every Napa/Autozone/Advanced store around. Blue squeeze tube, clean nozzle w/ little red cap. Haven't had the stuff leak yet on any motor/project.