guys, i'm having some minor issues with my '85 stang. it seems to be 'pinging' when i go WOT. it doesn't matter what the engine rpms are, when i punch it, i hear what sounds like a clattering coming from the motor. if i'm only 1/2 throttle it won't do it.
here's my set-up: 52k mile stock bottom end 5.0, with edelbrock performer intake, holley 585 carb, GT40 heads (upgraded springs??), crane roller rockers, e303 cam as far as i know.
i filled the tank up with 87 octane, and figured the car had too much timing for that octane (should have used 93 octane), so i backed the timing down to 10 degrees from 14. the plugs are autolite 104's gapped at 0.043", new distributor cap, rotor, and plug wires, fresh fuel filter. when i made those changes (decreased timing, lowered gap from 0.050 to 0.043"), the pinging stopped for a day, but now it came back. it doesn't seem to do it when the car is cold, either. i will add 93 octane as soon as the tank gets lower
furthermore, i took it on the freeway yesterday, and ran it pretty hard. i noticed that the car seemed to be running a bit hot when i was stopped at lights, or when i nailed it. when i got home, tons of coolant had been spit out of the expansion tank, and all the coolant hoses seemed tight as a drum, like the coolant system was pressurized or something. when the car cooled down, i had to add about 2 quarts of coolant to the radiator. oil looks totally fine. WTF?? blown head gasket?? how do i verify this?? could detonation have caused all this?? any help would be appreciated.