Brothers, the update is that after searching and calling wherever I could, i was unable to find a single 13B-T engine. So, decided to put the original 2F back in, as we discussed. The good thing is, the engine is as good as it could be. The engine oil is as clean as new. Even the existing carburettor is working fine. Clutch & pressure plates also seem to be replaced just before it was parked for auction.
Apparently, this engine was dead as it had all the spark plugs replaced and not even tightened back in properly, and same with the carburettor. It was rather hanging on one bolt. Almost all plug wires were missing etc etc.
I'v replaced, plugs, plug wires, point & clutch bearing. Hopefully rest of the things will also be such a blessing, Insha Allah.
The engine is back on frame and the vehicle will have the final paint job within the next few days.