Thanks for all the feedback. I have the '75 dizzy so no points. I time it with a timing light. Last I set it I think I tried 10 and 15 BTC. Will double check that.

I have tried two fuel pumps. Both of which seems to flow ok into a can while cranking. Changed inline fuel filter as well. Seemed be good flow and gauge reads about 3lbs. I even put inlet side of fuel pump into a fuel can to bypass the fuel tank and line to it.

I had the valve cover off and rotated the engine and watched each valve. Seemed be getting good movement on all valves. Valve lash was good as well. Going double check valve lift again.

On the exhaust. I had that all off when I did the M41 transplant. I had to replace the muffler. I was messing with the point dizzy back then. Put two wires on wrong and it back fired and blew the muffler apart at the seams.

I'm going to try running it with vacuum to flame trap and brake booster plugged.

On carbs I preset the jet till it was flush with top bridge. Then turned it down from there 2.5 turns. Its not run well enough to adjust this much while running.

The hard cold starts appear related. You have to crank it a good bit before it even trys to fire. Like I said. If I dripple bit gas into the carbs it starts right up. Carbs have fuel in them as I have cracked float cover and fuel came out.

I had my hand over carb inlet while someone cranked engine. I didn't get a whole lot of vacuum.

I have had the intake off a few times. Intake that came with car had secondaries which I had removed. I had the manifold off when I was switching to HIF6 so I could put on a new intake gasket. I found a repaired crack on the back of the intake. I got another intake with secondaries assume I found my vacuum issue. No luck. Then found another intake which never had secondaries.

Been trying to solve this for at least 2 years.