@Xulfiqar
I got my Khyber engine rebuilt a couple of months ago, both top and bottom end. It was blowing a lot of blue smoke all the time.
Ever since the rebuild, the engine shakes when under heavy load in a specific speed-rpm range, mostly around 2k-4k at 60-80 kph. It shakes enough to shake the whole car violently. Also, if the RPM falls below 900-1k, there is high pitched metallic vibrating sound from the engine bay.
Before the rebuild, one of it's inner joints was bad, but I don't recall that the car shook this hard. What could I get checked?
Aside from this, the acceleration and top speed is great; I recently took it on a long motorway trip and tested the top speed at around 147 kph (on a GPS speedometer).