sub frame bushings R&R
 

is it possible to replace the bushings without dropping the complete sub frame car was restored with aftermarket bushings but i found a nos set

Yes, I've done it back years ago. support car carefully by the rockers then use floor jack to lower sub enough to swap the bushings.

Yes. Shouldn't be a problem.

Also maybe loosen a few steel line (Brake-Fuel) as needed,

I need to do this.

Sample of Bushing (F body)
 

Me too

1968 Swap import Bushings for NORS GM parts
 

Done
Mine No Motor,
One side at a time, Front end loose A partial Project car.
Loosening Fuel and brake lines clips/retainers.
Jack body at rocker to gain separation distance.