Love my 68 dart 270 slant 6-runs great
HATE the initial start... with the black soot residue spewing out from the tail pipe- all over garage floor...YUK.... once its warmed up tho-- its fine. No problem. Dart does not smoke use or burn oil.
I dont wanna do any major head / manifold alterations just to solve this problem- its just an annoying pain in the butt .... i put a section of card board down for the soot stain- and just drive away when we are warmed up.
Any recommendations or info on this issue is greatly appreciated.
Gotta love this forum for all their expert advice and knowledge!
Thank you
HAPPY MOTORING

So just warming up? Tail pipe emissions?

I'd check the choke adjustment, and choke pull off for proper operation and adjustment.

How many times do you pump the pedal for a cold start?

Which carb do you have?