question about my duster

[duster 74]

was up i have a 74 duster gold i just put a new 318 in it and new tranny it is not acting right when i put it in gear it sometimes dies and we cant set the timing right we think it has a diffrent cam in it not a stock one because we bought it from a repo place brand new but not from a factory it runs good we just cant get it to wear it will run good and also we think it might have a vaccum leak it misses you can hear it so if you think you have any solution to my proublem let me know thanks

[typesix]

If it's vacuum leak, fix that first. Gaskets at carb may be dried up and allowing leak. I had such a problem with my former 74 Dart 318. Rebuilt carb and same problem, installed rebuilt carb and still had vacuum leak. Ended up sealing the horizontal gaskets on the rebuilt carb with gasket sealer where visible on exterior of carb and this fixed the vacuum leak. Spray carb cleaner around the carb gaskets (carefully, it's flammable) to see if leak is there, check hose connections.