1970 Nova SS 396 Help

[chitown]

Hi to all on this forum. I have a 1970 Nova SS 396 body. It shows 28000? miles on the odometer. It is missing the original motor, 396. From what I have been told the car is an original big block car,by the heater core and the radiator support and it has all the emblems and markings. Its last big event was in 1982 at the Car Craft Street Machine Nationals. I purchased it in 1983 before all the hoopla and cloning of Big block cars became popular so I am pretty sure its a Big Block body..It looks to be a 4 speed, bench seat rubber mat car.I was told a few years back that a dealer on the East coast had ordered all the Big Block Novas, but then came a recession in the economy and the cars went their merry ways. My question is what motor? L78 or L34? I found a little 4x8 paper under the back seat but it seems to deal with the interior trim codes. The vin is 11427ow303XXX. Anybody have any thoughts or onfo on this. Thanks....