blacktools

Hi guys. I need your experience !:icon4: I went to see a 280zx '79 156k kilos man. n/a the body is clean ,floor is clean ,frame ok. The troubles starts at the engine. the (stup!d omg !) guy putted some boat gaz in the gaz tank (1/2 oil , 1/2 gaz) so now the engine do starts but sounds rough and don't keep a stable rpm. the ''dude'' said the troubles started Before he putted boat gaz in and he also said that a guy said (...) that it was yhe regulator or the gaz pump. SO ! i want to know before i buy the ZX if its just a stupid thing like a regulator and boat gaz (OMG!) or it's something much more bigger like a blown piston . the engine looked realy clean (no not-collected wires etc) and he didn't had sinking oil. I've smelted the oil dip stick and it smelled a liltle bit the gaz without any metal particuls. So ,thanks a lot guy ,i'am a long time fan of nissans but i don't have any experiences:icon11:(i love to trick out some engine so i dont care about swapping parts or little things but it's a another affair if its a piston.. THANKS ' blacktools