hi, i have a 91 vp commodore and if i put the key in the ignition and turn it over it takes about 5 seconds for it turn over, but if i put my foot on the gas, either a little bit or a lot it starts instantly. once the cars started runs perfectly no problems at all,also do other holden grills fit my model say a statesman/caprice/someother models with out mods, like will the bolt straight on?
with the starting problem, if its cranking without starting for 5 sec's id say to look into your fuel system firstly. change the fuel filter, have your injectors ultrasonically cleaned (or buy new ones) and clean out the fuel lines and rail by running some premium fuel and absolutely give your car heaps, lots of full throttle.
also take off your throttle body and clean that right up with some carby cleaner, making sure to clean out the IAC valve area and ports where the air passes through....give the IAC valve itself a bit fo a clean up too to get the gunk off it and spray some contact cleaner into the spring part to make sure its working freely.
as for the grills, pretty much any grill except the ones you mentioned will bolt straight on (clubby, aero, ss, sv5000 & sv3800, will all work...from any vn-vp).
the statesman and caprice grills are part of the bonnet and as such you would need to modify yours for it to work.