The best thing you can do for your current engine is keep the rpms down.......no 6 thousand rpm runs.......more than likely your not making anymore power at that rpm than at 5500 max.
The rpms will do the most wear on the engine,with high rpms your more likely to blow than lower rpms.
I have a 5.0 mustang and keep the revs at about 5000,it might make a few more horses at 5500 or 6000 ,but it`s a 1986 with over 200,000 miles on it and it still passes emissions.Been runnin the snot out of it for years and its still runs great.........if it blows it will not run at all.

Save the all out runs for a forged piston and crank motor with good rods in it and high flowing heads,I would run that motor as is and get another engine for a performance build,considering you will only basically be using the block from that motor,those heads are going to max at about 400 hp anyway,no use spending any more money on them and no use putting a forged bottom end under them.
That would be my plan of attack.