cold no start, valve job?

My 1979 240D with aprox. 300K has run OK with a slight miss at idle when warm. The first time the temperature fell below freezing the car would not start and now at 50 deg outside with a heat lamp on the block and starting fluid I can’t even get it to pop!
I had thought about doing a valve job in the future in hopes it would solve the miss but have been afraid of what might happen to the bottom end, you know, blue smoke out the tail pipe and who knows what else.
When I crank the engine I get a puff of smoke out of the intake manifold with every revolution. The starter also seams to surge in tune with the puff of smoke. If I hold my hand over the intake manifold I can feel pressure along with the puff of smoke.
I would like to get the thing running again before I pull the head off in case something else is making it not start.
Talk about frustration, any help would appreciated.