so on my 80z we put a rebuilt 350 in with a few upgraded parts like flat top pistons and such. but when i drive under a load, the engine starts to ping. it only pings though when the engine is warm. when i leave my driveway and put it under a load getting on the the highway, it wouldnt ping but if i did that when its warm it would. also just driving like normal on a highway or something it would ping during the accelleration on the on ramp but not while just driving on it. i have the timing set at 10advance. Also, would it make a difference about our carburetor. we have a edelbrock 600cfm on it with stock rods and jets. what else could be the problem?

 

Put premium gas in the tank if you haven't already. Your engine is either asking for a higher octane due to your c.r., less timing advance, or both. 10 degrees at idle should be close to fine, but where is the timing at when it's all the way in at the higher rpm's? If you don't have timing tape on the dampener to check it, you won't know. But since you're only getting pinging when the engine is hot, you're getting pre-detonation. Suspect your gas first.

 

I tried running 93 and 87 for awhule but that didnt change much. Im also gonna try changing my fuel pump bc thats getting pretty old bc we were in a pinch and had to use the old one

 

Since you increased the compression, which makes the engine more prone to pinging, there is a possibility that the spark pugs are getting too hot, so you could try spark plugs with a colder heat range and see if it helps. Pull the plugs right after a hard run and see what the tips look like. Also, assuming that the spark timing is correct, there is always the possibility of too much compression with a short duration cam, which can cause excessive combustion pressure.

 

cool. il try picking up some new plugs tommrow and keep u guys posted

 

So i threw in some ACDelco R45TS's in with a .045 gap and they run great. Thx guys

 

Good deal!