High 17s, Maybe a 5.0L TC, not a Vic though.
4.6 is a solid motor. No, its not that classic time tested pushrod technology that hasn't seen a substantial change in 50+ years, but that isn't a bad thing. Times change, engines evolve, and this is just the next step. Its not even ground breaking revolutionary stuff here. Hell, Ford had overhead cam engines in the 60s. Overhead valve motors date from the 30s and probably even before. I've seen plenty of 4.6 engines well over 200k without any major issues. Hell, taxis are often pushing 400k when they are retired. For longevity, I'd honstly lay my money with a 4.6 vs a 5.0. On the other hand, if I was picking something for avaliable and easy performance mods, it would be a 5.0.