Thanks for the replies.
It's just the smallest puff of smoke when it actually dies. Sorry I should have been more detailed.
As it turns off it does the puff of smoke. No backfiring though.
First sign is power backing off even with foot to the ground. You can then back the foot off, try and put it down and it's like it's fighting to get the power but having coughing fits, you do it again and it takes off like a rocket. A few more times with this happening and power is all but completely gone. Happened the other day after half an hour of 100+km driving and then luckily a couple of streets from home it happened. We ran her slowly home the last 2 streets and she died in the driveway (Luckily). Won't start up afterwards. Mary tried kicking it over last night with a brand new yellow top battery. Nothing. Just cranks but doesn't start.
Runs solid prior though. If it was warn piston rings, timing or distributor for eg wouldn't it run shocking the whole time? It's been a discussion between Mary and I. If something was off for example a setting, or a cylinder not working, she wouldn't run right at all I'm guessing. Would be lacking power. When we had it sent to a mechanic around here because we thought we picked up water in our fuel at a service station, he said no to contamination in the fuel but said he needed to clean the points on the distributor. Said it would take a bit of running to clear it's throat and run properly and to run it for half hour or so and things should be back to normal. This is the reason why I took it for a half hour drive.
Started out slow and then opened her up on the country roads. But before we knew it she had the same symptoms as she did when it went to the mechanic.
Wish I could get it to Sydney for a checkup but she wouldn't make it that far and can't afford towing.
It's a shame because it's hard to find good old school mechanics. I don't know people out this way at Bathurst.
I'll have to research what a pcv valve is. Still got a lot to learn about mechanics.
Appreciate both your help.
Tommy