What's the correct way to Prep and paint my 69 slanty.

remove rust, clean with "wax and grease' remover, or pure d enatured alcohol. the factory just shot them with single stage enamel. along with overspray on things like exhaust manifolds that were already attached to the engine prior to paint. any type of paint will eventually burn of the exh manifolds I figure. maybe some of the guys with the big budgets have found something??
Yeah ^^^^^
And the cooling bypass hose with the spring type hose clamps was on the engine when painted at the factory.
And when I took my original 64 apart, there was red over
spray on the aluminum 3 speed manual bellhousing but it was mostly natural cast aluminum. And if you really really want to get into the nitty gritty, there was over spray on the flywheel through the starter hole. With the engine at TDC the red patch lined up perfectly. I find stuff like that interesting.
I bead blasted my exhaust manifold and sprayed it with Eastwood high temperature gray exhaust manifold paint. Then baked it in a powder coating oven for awhile.