help! my 66 is sending smoke signal

[10zz964]

Hi,
I am in a process of running in my engine after a full rebuild. Tonight while i was driving suddenly the oil pressure was low, idle was really low, engine almost stall and there was strong fuel smell in the car.
I pull a side and turn off the engine. There was a big puff of smoke come out of the exhaust as soon as i turn it off. there was a pool of oil about 4" in diameter that came out of the exhaust on the ground.
there is a fuel leak from the area in the picture. just on that side.
I let it sit there and afraid of cranking up the engine as the fuel leak look pretty serious.

the engine is 2.7 rebuild Webber, je piston 9.5:1, s cam.

any though how this could happen? what and where should i look for? any suggestion would be greatly appreciated.
thanks