Detonation under acceleration

[K5owner]

I am kind of stumped on this one so I am throwing it out there to you guys and see if a fresh set of eyes and guide me. So some background first, I am the third owner of a 1984 K5 with a factory 350, 700r4 with a/c. The original owner was the City of Norco in California. This is a CA emissions vehicle with the CCC quadrajet and no vacuum advance on the distributor. It is all controlled by the computer and associated vacuum devices. It is a very original vehicle so I know this is how it left the factory. Okay now onto the problem. I recently had the carb rebuilt because I was getting the typical leak from the casting plugs and had some throttle shaft slop I wanted to get rid of. I get the carb back and it runs well until I get into the throttle then I get pinging or detonation. On light throttle and partial cruising it is all fine. Here is a list of what I have done so far:

new cooler autolite 24's (factory calls for 26's I believe)
new cap and rotor
new plug wires
new water pump
new radiator
rebuilt carb
adjusted timing to 6 degrees per underhood specs
fresh 89 octane fuel

Now I have read a faulty EGR valve can cause my issues as well as temps that are too high. The truck has always run at 210 no matter what. The previous owner lived in the mountains and put a warmer thermostat in it to bring up his heater temps for interior comfort so I know that isn't how it is supposed to be. Another thing is when I tested the EGR valve it will hold pressure but bleed off pressure slowly but noticable on my vacuum pump. I ordered a new (correct GM part number) EGR valve and a 192 degree thermostat to replace those two things.

Now mind you I never had any issue with this truck pinging BEFORE I had the carb rebuilt. In fact it had more initial timing (12 degrees) in it before I rebuild the carb, it ran fine other then being rich from the carb issues i described. So what do you guys think? Carb? EGR? Temp too high? I am kind of running out of ideas here. I have yet to touch anything on the carb since getting it back from the shop that rebuilt it in fear of chasing my tail. It ran good out of the box as they live test and tune the carbs prior to delivery to the customer. Is there any APT or secondaries I can richen on this carb or adjust? I need to get it running solidly as this will be the rig we take for thanksgiving camping here next week. Thanks guys I appreciate any help.