360 block limits

I’ve run 100hp kits on junkyard ****. I’ve also run a 300 shot on a 4 cylinder bonneville car. The OPs engine will be fine on a 100 shot. The strength of the components is a non issue. 200-250 I’d start to worry about your cast crank. System set up and tuning will be key to making it live. Do NOT run it lean and DO NOT let it detonate. I always suggest (lots of threads here) a dedicated fuel system for the nitrous and some way of pulling timing on the hit. Don’t just pull a few degrees by cranking the distributor. Make sure your off the bottle tune up is tits before you ever hit the button.
Carbs and EFI both have their place with each having benefits and downsides. Jason line and Greg Anderson are two of the smartest dudes racing and both of them prefer carbs because their intake manifolds have design and testing that rivals NASA. The intake has more to do with distribution than what’s on top of it. Carbs pull a lot of heat out of the air charge and there’s lots of power there. On the flip side efi has individual cylinder tuning to combat distribution issues. BUT ask a few of the LS guys how many engines they’ve scattered with NOS because they spray right into their long runner dry manifold, the answer is lots of them. It all comes down to tuning your particular combo and not getting greedy.