I removed that engine from the car after I melted a piston(at 18K).
I replaced it with a brand new bottom end which I still own and is awaiting fitment to my 1981 Derby.
I sold the car in March 2000 to a friend who had a written off Mk.2 G40 conversion. I put all his running gear onto the genesis shell. That engine had done 40k when the shell had done 153k. I had heard a rumour that it'd had gone bang again last year.
If I were you, I would check that the fuel pump has been replaced as it was still running the standard SPi pump when I sold it(which caused the demise of the cup car engine). Being young and stupid back then and no access to the internet, I didn't know there were two types of fuel pump
And no, the guy you bought it off didn't build it, I originally did, but it's probably been apart many times since then...