Got the replacement HEI distributor fitted,kindly sent over the pond by fellow bolter Neals49.
Initial start up was disappointing to say the least,I thought i'd screwed up the valve timing etc until I discovered the loose ground wire inside the dizzy! blush
The engine's running like a champ now,no popping and f*rting.....
Now to rack up some mileage!

1950 Chevy Advance Design 3100 in Scotland
In the Stovebolt Gallery
More pix on Flickr.
I've definately got this truck thing in my blood ... my DNA sequence has torque settings
"Of all the small nations of this earth,perhaps only the ancient Greeks surpass the Scots in their contribution to mankind" Winston Churchill.