Rough Idle Problem- 1967 Valiant

Thanks for all the replies and tips everyone! Work got busy this week, and I haven't had a chance to look at this again until today. A few updates. After adjusting the valves, it did run noticeably better, but still would not idle without feathering the pedal- especially when cold. Also, it was definitely running lean. At idle, I could slightly close the choke and it would run smoother.

Last night, I pulled the intake/exhaust off and found that the exhaust manifold has a hairline crack on one of the exhaust runners that was starting to leak. I have several spares, so I am going to replace it today. Also got a parts carb that I'm going to go through today to see if it's fixable. All my spare exhaust manifolds are the newer type with the open choke stove area, so I'm going to have to see if that will work. I have the newer choke stove too, but it looks like it has a heating coil in it- not sure if I need to hook that up?

Also, to ensure no leaks at the manifold to head surface, I've always left everything a little loose, tightened the manifold to head nuts, and then the 3 intake to exhaust manifold bolts. Is that the right way to do it?

Anyway, we'll see how things go today. I will give an update once I have it back together and running. Thanks again! :thankyou: