Triumph Repair: 76 Spit engine rebuild, toyota 4age, kerosene

Question
Was given a 76 spit 1500.  Prev owner was driving it when the engine seized.  Removed plugs and injected kerosene and allowed it to set for a few weeks.  Hooked up a fresh battery and get only a starter selonoid click. There are about 50k miles on the car.  
? What can I expect to pay for engine parts for a rebuild
? What enhancements can I make over stock to improve horsepower?
Am considering swapping the engine with a Toyota 4age for improved performance and reliability.  

Answer
sorry for delay, I wouldn't put another kind of engine in it. it leads to problems. i haven't rebuilt any engines in a long time so i don't know prices right now. just do some searching and see what is out there. Dave. !!!!!!!!!!!!! there is nothing about a FIAT in this. what is the feedback suppose to mean? it is some one like you as the reason I'm getting out of helping with this.