Hi Dan, probably pushrod tube seals or valve covers leaking, you can replace them and solve the problem, not a hard job

 

a few pictures of the car, the thing was fully rebuilt. hopefully not push rod seals lol

the snorkel arrangement i threw on because there was nothing there after the restoration, the intake was drawing straight from the engine bay

 

looks strange up under there, can see that it is an early model by the shifter arrangement, but the exhaust looks funny, and there is no reason to have that "snorkel" installed. That motor is for the heater blower, and just draws supplementary air to help blow the heat to the front of the car when it idles.

 

it is easy to get a valve cover cockeyed causing a leak. In fact just happened to us with a car we finished. Drove it around the block and it was smoking! Valve cover was cockeyed

 

Hard to see: heat exchangers?

 

The heater arrangement in a 914 uses exchangers that surround the pipes that carry exhaust from the heads to the muffler. The air in that chamber gets heated by the exhaust pipes and then the heater control boxes allow it to come up into the cabin or not. The blower you show is designed to blow air through that chamber and into the car when the red lever near the gearshift base is lifted all the way up (see last pic)

if the car has heat exchangers are they the stainless steel ones or regular steel ones? Its possible that although they look OK from the outside, the inner pipes that actually carry the exhaust are rusted or have a manufacturing issue that is leaking exhaust into the surrounding heat chamber and then that's coming straight into the car via the heater ducting. Also, check to see that the heater control boxes have the cables in them adjusted properly to allow the springs in the boxes to fully close the flaps and not allow leaking into the cabin. This will help if the smoke is only occurring on startup and then goes away when driving, but you need to check the integrity if those exchangers because if they're bringing in smoke they're probably also bringing in carbon monoxide.

These are the stainless version heat exchangers I bought from dr914 32 years ago that are still on my car today!

 

beautiful, so beautiful that you need to install two missing emergency brake cable boots at the rear calipers!!!! (LOL)

 

Nice catch, and yes, probably so, though it's really only a fair weather car when I can help it.