Detonation problem

[5.0 Fiend]

Colapsed lifter maybe? On my last engine, I changed the oil to valvoline 20/50, and when I started the car, it had this awful knocking (so bad, my buddy half a mile away heard it), I tried playing with the dist to see if it was fuel knock, didnt help, tried pulling plug wires, no change, took it for a test drive and thought it would be safe to drive 15 miles to work the next day. On my way to work, I got tired of the noise and decided to hop on it to drown out the noise, and at about 4500 rpm it stopped, then I was like finally! The next thing I know, the car goes pop, and I look in the rear view to see a giant cloud of whiteish black smoke, got out and looked under the car, and sure enough there was oil and coolant coming out, (luckily I was about a mile from my house). As it turned out, I put a rod through the oil pan,(guess the new oil put too much stress on the motor). Oddly enough, the car started, but only wanted to run on a couple of cylinders. I guess your options are baby it, rebuild, or replace, it sucks to have your stang out of commision for any amount of time.

[KiltedBanshees93GT]

I dont think thats the case, she's been running 20-50 for like 8 months, no abnormal lifter noise, and the car seems to do fine except when a heavier than normal load is placed on the engine at lower rpm.
Oddly enough, the car seems to have the biggest problem when I'm heading to work, then on the way back, it seems to happen less often. Odd considering I'm driving the same roads. Maybe theres something with my driving style, or I'm just usually too whipped to notice it on the way back

J