Slant six cam

Kinda depends on your driving style too. As a DD, and if it's an automajic, if you never go past 3500/4000 it might be fine. and with solid lifters at least you don't have to worry about lifter pump up. And if you have flat tops,the likelihood of piston to valve interference is low. So even if the springs do give up, the onset will be noticeable, probably/most likely, without any damage.....................Unless it spits out the locks........uh-oh.................

But if that 6 has hydraulic lifters....OR, if you like to buzz it up...........Better put some springs on it.

Alright, alright, you convinced me; put some springs on it, cuz they're cheap insurance.