few questions for a 72-idle with carbs? need for engine tin? front struts?

hey my name is alex and im kinda familiar with this forum site. i have owned my 1972 porsche 914 for about a year and half now and finally, after about 5 years of sitting, got it running. HOWEVER, this car seems to want to do the strangest things. sometimes it will idle perfect, but once i actually start driving the car, it starts popping and is very jolty. now the car will barely idle, or simply die. i have messed with the distributer, and i beleive its a timing problem (vavles apear to be in good shape). if so, can anyone help me with the timing? (the car has dual webers). also does anyone know if the engine tin is really necessary? also i seem to be seeing 914's lower in the front than others. is this just because of the choice of struts or is it the suspension. thank u