Pinging 350

[dcurtis]

Just wondering if anyone could explain why my 350 could be pinging. Under normal driving conditions it drives great but if your just cruising down the road and give it about a quarter or so more throttle the engine will start to ping. From a dead stop I can stomp on it and it burns the tires through 3rd gear easily with no pinging at all, I stomped on it because I figured if it pings at low rpm's it would ping at higher rpm's but it didn't.
Someone told me that I may need a cam with a little more valve overlap to drop my dynamic compression ratio, and that my current comp 270H doesn't have the overlap i need for my compression, which is about 10.36 by my calculations.
Other than that I have no idea what could cause the lower rpm pinging and any help would be great.

[dr_bowtie]

What octane fuel are you running....

Most common cause is to much "Vacuum" advance at part throttle

You either have to limit the amount of advance caused be the vacuum advance or simply buy an adjustable one....Easiest way to tell is just to unplug it and retest....If you are not running a vacuum advance your mechanical may be comming in too soon which you will also have to limit or just back off by 2 degrees...

Depending on how efficient the cylinders are total timing at that compression should be no more than 34 all in by 3,000rpm...

[dcurtis]

Always use 91 octane fuel, I have a curve kit installed right now, should I maybe put in the stronger springs to limit the advance?

[dr_bowtie]

You may try it....But first I would run it with the vacuum advance Unpluged and see it the ping disapears....if it does you have too much vacuum advance....if not

Back off the initial 1 degree or use a heavy spring on one side and retry.......