72 duster resto
I'd definitely do suspension. I did a similar swap with a 72 Swinger I had back in the late 90's... It was a great driving car until I swapped out the 225 for a freshly rebuilt 360... The 360 ran fine, but the car never drove right after that as far as handling/stopping... I was only about 20 years old with super limited funds and kept adding more parts to try to get it to handle/stop better, but never got it there and eventually ended up selling..... Now 20+ years later I'm doing a Scamp and started the process with better suspension, brakes, etc and this one now handles/stop world's better than my old one ever did.... But this time I decided to skip the motor swap and do the supercharger on the 225...
Long story short - Based on my experience, I'd do the torsion bars and anything else you can do easily to improve the front suspension lest you end up with a crummy driving experience like I did with my first one.