I didn't see easily from that video that the black Firebird that BB was racing but I think is KC Firebird. That car is very consistent and sits low in the rear and higher up front., somewhat like an older style gasser. The Firebird hooks street or strip and is quite often in the winners circle. Its very common to see loose bags of lead shot in the trunks of street and no-prep track race cars.
I have a zero-prep street car that used to have 100lbs of lead bolted inside the rear bumper, ended up moving the engine back 10" so I could stick radials without the lead. Depending on fuel load, F/R distribution can be as high as 43/57 @ 2495lbs. About 10" of extension up front.
Grant