You're getting a little closer to knowing exactly what you have...
VIN.... L346855 is a July '68 production car..
C130 if It makes any sense (13 March 1970 cast engine block, assembled 24 March 1970; installed originally in a '70 Corvette with 350ci/300hp/4sp)
the Rear axle ID is BU0925G2 E (3.73:1 Posi 12 bolt - could be from a '68 or 69 Camaro.. assembled 25 Sept)
4-speed muncie ID P0510
Does the engine pad have a VIN on it? mmSnnnnnnn or ??