I just purchased a 93 Formula. It has the LT1 with 125000 miles on it.
Had the head gasket replaced before I bought it.

The Car has Spark Knock after its warmed up. Even on Take off now.
If I am running 2000 rpm in 3rd then give it half gas pedal it starts spark Knocking. If I go through and wind out the gears....... raise the rpms for each gear it's fine. I changed the plugs and knock sensor since and still same issue.

Where do I look next?

Thanks,
Dave

 

If you can actually hear "spark knock" (detonation), you engine has a serious problem. There is a knock sensor and a knock retard system in the ECM that can pull out up to 15-degrees of timing advance. It pulls the timing out BEFORE you can hear the knock, if the system is working correctly.

 

I changed the Knock Sensor already. I just talked to the guy I bought it from. He filled it with 87 octane gas and had a head gasket changed, so Maybe the rockers might need adjustment? I know I need to get the low octane out and higher in. and change the gas filter.