hey every one i am johnny a new mamber i have a 70 dart dart slant six, in excelent looking condition,
first problem
1 engine runs a little shakie but relativly good, put into gear it dies immediatly

every one says it a vacum leak, but me and 3 friends have looked for days havent found one, and checked plugs gap, new cap and rotor, what else could cause this problem, does the plug gap change when i have electric ingnition

Have you checked the valve lash yet? .010" intake and .020" exhaust measuered hot. The plug gap is .035" with either points or electronic, though some people like .040" gap.

what is the valve lash

The gap between the rocker arm tip and the valve tip. To tight and the valves will hang open. To loose and the valves will not open all the way You will know if they are loose by "ticking" noises comming from the valve cover.

no the engine runs very quite, its just stalling when i put it in gear