Depends what options the leviathans take. Those one-use phosphex launchers would make a pretty nice mess of the infantry.
And I wouldn't garuantee killing them from across the board.
All the D shots would nuke the 8 models before they would move and run the 48' they would need to get to me.
Read the original post:
Reaver Titan with Gatling Blaster, Reaver Power Fist, Apocalypse Missile Launcher
No destroyer weapons (except in close combat).
I'm not actually that scared of the individual leviathans because they need a '6' to hit - not being superheavies. Sadly, I'd need a '5' to hit them, because astartes dreadnoughts are WS5 in
HH games. Still, between their frontal armour, 4HP, and atomantic shielding, taking more than one or two out at range is probably wishful thinking.