Back firing is most likely caused by the ignition timing being retarded. What do you mean by "Blowby?

I think you mean lots of blue smoke from the tail pipes?

If that is the case then with so few miles on the engine I would suspect some worn valve guides caused by burning unleaded fuel in an older leaded fuel engine.

Provide some more details if you have not solved your problem.

Answered by jackdo
2 questions asked

check the pcv and ign timing .

Answered by jerrygoodwrench
2 questions asked

most likely what you are experiencing is the carburetors are flooding, that would cause excessive smoke from the tailpipe due to the fact that you are burning all the oil that is lubricating the cylinders, that is why the smoke is blue. I can come repair the vehicle but you will have to buy me around the ticket and expenses it will be cheaper than taking it to a shop

Answered by Dr Loot (expert)
2,176 answers provided

you asked me if car for sale yes 30000 for the car
and no i did not hot rod it

Response from dom35
2 questions asked

were you able to repair the vehicle? where are you located? send me some photos to davidgedo@gmail.com

Answered by Dr Loot (expert)
2,176 answers provided