Rough idle on 440

I have a 440 that I have been trying to figure out. It has a rough idle. I believe it has a vacuum leak. The cam is a older Hughes brand that has around 228 degrees duration at .05 lift. So I think idle should be OK. The engine is rebuilt with all new components. I had the heads milled and the intake milled to match. When timing the engine the timing marks do not line up were they should. The timing marks are off by arround 30-40 degrees. The damper may have shifted but I don’t know for sure. The vacuum at idle is about 7 inches.

My questions are

Would the engine idle OK if the timing chain was off by one tooth?
What affect would that have on were the engine liked to be timed?

I plan on putting on a new intake manifold gasket set and getting a new dampener but I would like to rule out the camshaft being out sync before I start.

I drive the car and it seems to run fine once off idle.

Thanks
Sanman

Quote:

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The timing marks are off by arround 30-40 degrees. The damper may have shifted but I don’t know for sure. The vacuum at idle is about 7 inches.

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(1) Find exact TDC w the ten dollar tool. (2) pull pass valve cover/all plugs & hand turn front crank bolt w 1&1/4" socket/short extension/breaker bar until both of #6 cyls' valves are open and moving and are open the exact same distance & at that point (rockover) the timing marks on the dampener should be within several degrees of each other (could be a slight bit more if sloppy chain). Not a cam guy so not sure how wild those specs are. What carb? Always idled bad? #1 get the timing right & yes may very well be a vac leak. What timing are you showing? After typing this I'm thinking setting the timing right may very well take care of it. Post any news!