I inherited a 68 firebird convertible in fair shape. Very little rust, dash is in good shape. Seats, top and all the foam molding needs to be replaced. Here is my dilemma and options I am considering so any advice is welcome. It does not have the original 400. It has the original automatic transmission with a 350 in it. It probably hasn't been driven in 25-30 years.
Option 1: the engine isn't frozen. I can turn it by hand. Can I assume all seals and hoses will need to be replaced? Will I need to have the engine rebuilt? Or just seals and gaskets replaced and give it a tume up? I assume some parts fuel pump, sending unit, alternator, ac charging will need to be dealt with. Can anyone give me an idea of price for option 1?

Option 2: find a 400 that is in good shape so it is what it was supposed to be. This might be a silly question but if I find a working 400 it would include alternator, fuel pump, water pump? Correct? Or would it just be the block, and use those existing parts off of what I have now? What would option 2 cost?
Option 3: restomod the engine and transmission to something more modern? Not looking to race it but have to have a v8 able to leave nice ling black marks. Don't really like it just having a 3 speed automatic. Ok for Sunday drives but not something you want to hope on the turnpike in and set the cruise at 85-90 fir four hours. Had an old 4spd manual83 mustang gt 5.0 302. Fun around the city but hoping on the highway engine just needed more gears. My current car is a 300s only a 6 cylinder but at 85-90 I'm only at 1500 rpm with the 8 speed transmission. So what would the cost of option 3, modern v8 and modern transmission run. Thanks for all the info