Perhaps you can weigh in on the cause of engine smoke.
Here are 2 videos I made to help:
part 1 - before start walk around - http://youtu.be/nRr-KT2fPDQ
part 2 - running and smoking - http://youtu.be/rzUaq0Izy20

The car starts and sounds great, but once it's warmed up, it develops moderate/heavy smoke in the engine bay and the cabin fills with a good amount of smoke/fumes.

Here's what I think are the possible causes could be, let me know what you think:

A) Exhaust manifold to downpipe (over torqued, under torqued or misaligned)
B) Exhaust/Intake gasket (leaking)
C) Valve Seals - leaking oil
D) Leak at injector value / copper crush gasket - burning fuel
E) Head Gasket - coolant steaming
F) Other

The smoke is not easy for me to identify - it's not bluish and there is little smoke out of the tail pipe. It doesn't seem like steam either nor do i detect a sweet smell.

I suspect it's exhaust leaking from the downpipe connection (A). I did recently replace the exhaust system from downpipes back. They are custom stainless steal downpipes I purchased used. I used new oring gaskets inside/between downpipe and the mainfold and new 10.9 bolts/nuts to secure it all. I am not too confident in alignment or torque. Manual says "Hex Bolts or nuts from exhaust pipe to exhaust manifold - 2.5 kpm". That's 18 ft lbs which isn't much torque at all. Also the joint seems a bit like a wobble socket extension. If this is the problem, I'm not sure how to correct it.

A bit more background in case it helps.
-1972 280 SE 2.8L, but has a 1970 280se 2.8 engine and trans. I've done a lot of work transplanting the engine. Donor engine didn't seem to smoke before transplant.
-This car hasn't been road tested yet.
-The Manifold and gasket to head is original.
-I've pulled, swapped and cleaned the injectors. They are all spraying nicely. I reused the metal washer/gaskets.
-Valve cover gasket was replaced
-All valves adjusted to spec
-installed pert ignit 2 with coil. New plugs, newish wires/dist cap.
- timing has not been checked