I've found golf tees to work great for plugging the fuel line! I've used them on my '70 but haven't tried them on my '78 which I think has 7mm ID instead of 5mm ID fuel lines. It should still work though since the golf tee flares.
#2 Pencils work well too. I have also used thick shaft Phillips Screwdrivers too. Just tightened the clamps back down on the screwdriver once inserted into the hose.
I like the petcock idea best. Ciao! Chris M. <Busbodger> Cookeville, Tennessee ICQ# 5944649 scm9985@xxxxxxxxxx '78 VW Westfalia (67 HP -> that is...67 Hamster Power) '65 Beetle - Type IV powered '99 CR-V station wagon '81 CB900 Custom moto-chickle 2.5 Corvair engines for my Trans-vair ConversionFOR SALE: Early model Corvair engine - needs bell housing, otherwise complete (make offer)