I have an 87 IROC with a 350 4 bolt main, and i get a pinging sound from the engine compartment when i floor it. Was wondering was it a spark knock or improper carb adjustment(edlebrock performer series). Also, what is the proper spark plug gap for my engine. All help is greatly appreciated.

 

What are the specs of your engine? I wasn't aware of any carbed 350s out of the factory in 87.

 

My guess would be a 350 was swapped in place of the 305.

Can we assume that you have a vacuum/mechanical advance distributor in place of the stock computer controlled distributor to go with the Performer carb? If that isn't the case, get one in there.

If you do have a vacuum/mechanical advance distributor, you need to have the timing set correctly. The vacuum should be disconnected and initial timing set at 8-12 degrees at idle. If it pings at 12 degrees, back it off to 10 and try again.

If it pings at 6 degrees, something else isn't quite right.

Try a plug gap of .045".

So, what are the details of the 350 in there beyond the fact that it's got 4-bolt main bearing caps?

 

I'd check your timing, and if that dosent work put a better grade of gas into your car. Bad gas (87 octaine) will cause a car to ping faster then 93

Muirner