Rep Power: 0

My car I recently bought was swapped with a vtec head(unknown) and a d15 b1 block.. I was told this is not good... but don't know much.. the car did run good.. but lacked power.. so I replaced fuel filter and it still wouldn't start without foot on gas now.. so I checked and had to replace spark plug(X1), then it started fine and ran best it ever had. Then I drove it about 35 miles with 3-4 hours in between about half of thirty 35 miles, now it won't start.. and won't even bump start.. any help??