rhoads lifters?

I have them in my 340 and they seem to work great, especially with a bigger cam. It still has the lopy sounds and is very drivable on the street, lots of low end tourqe. They claim to have a slight HP gain too. If it were up to me, I would install a new cam, the lifters can be expensive, it would be a bummer if the used cam wore them out. You should be ok putting in new lifters, just make sure to use plenty of cam break in lube!