Well...did a seafoam on Friday morning. Put a bit into the crankcase and ran the car for 5 mins or so and did another oil and filter change.
brought the car on about a 120 mile round trip to my GF's parents. Car ran awesome, got about 34 MPG. No knock on startup, even on Saturday morning when it was about -15* overnight.
however when leaving from work today, the car did it for literally 10-20 seconds, then went away. This knock sounds pretty damn horrible too.
I'm just about to say pi$$ on it and tell the guy $500 and its yours.
This car ran awesome up until i took the top end off. I just dont understand what could be causing this? Before i did the top swap, the car ran like a dream too.