When I bought my car it didnt have a manual with it. Does anyone know what grade of gas the manual suggests to use? Its just a stock 87 350 TPI with the timing set at the stock 6*. Thanks!

 

I run 89 in my '88 350, and I can still jab the throttle and it not ping unless it's during the heat of summer - and only then it's on upshifts at high throttle levels. I even run 89 with no issues when I have my Fast Chips/Ed Wright chip installed.

If you have excessive oil consumption due to poor valve seals, then the oil's presence in the chamber will in effect lower your octane and potentially cause pinging. The oil will also increase the accummulation of carbon deposits on the valves. Those create hot spots in the chamber that will cause pinging.

If you ping on anything less than Premium, you should make sure your cooling system is in good shape, and you can run GM Top Engine Cleaner or "Seafoam" (sold at auto parts stores) to clean up the chambers and valves. I'd also recommend running Chevron's Techron fuel additive every so often (maybe at the same time you change your oil).

Oh yeah, I have my base timing set at 10*, too.

 

stock compression is 9.3:1 so 87 will run but i would suggest 89 if u dont want to do the 93, i run 93 with my motorvation strip chip and my base timing set at 8* on my 87 350tpi

 

Its a "high-performance" car, so the manual says to use premium. You can run 89 or 87 if the car doesnt ping, but usually it will due to age and carbon buildup, as described above.