You wil find all sorts of opinions on head gasket installation, but the first and foremost thing to do is get everything CLEAN! With a freshly-decked block, and whatever cleaning the machine shop did during the magnaflux procedure, you've got that one covered!
While the spray sealers are OK, a lot of us oldtimers grew up using brush-on liquid sealers before spray sealers were invented. My favorite is Permatex Super 300. It's a dark brown, almost black thick liquid that seals seeps and stays tacky about 3 days past forever. The more common 3-D or 3-H Permatex brush-on doesn't seem to seal as well as Super 300. Give the top of the block a good even coat before installing the gasket, and brush another layer onto the top of the gasket before putting the head into place. Use either a little sealer or maybe anti-sieze compound on the head bolt threads, and put a little dab on the underside of each bolt head to help lubricate it during the torquing process and seal any coolant that might follow the bolt thread and creep out from under the bolt head. If a bolt doesn't need lubrication, it needs LocTite, and head bolts are definitely in the "lubricate" category. I like to do a 3-stage torquing process, warm the engine up, and retorque, unless I'm using a gasket that specifically says "do not retorque" in the installation instructions. Even then, I'm sorely tempted to do a hot retorque! Good luck!
Jerry
http://www.permatex.com/products/Au...atex_Super_300_Form-A-Gasket_Sealant.htm
