Getting ready to detail the trunk on the 70 and I find that the surface is really rough. It's almost like it has undercoating that is very hard. There is no spatter paint, it's just black. Has anyone else encountered this? If so, how did you prepare the surface for the spatter paint? Reading other posts some have taken the trunk to bare metal, primed and shot spatter paint. What is the best way to handle this?

Good question. I'd like to hear opinions. I was going to wire brush the surface, vacuum good, then go over it with some spirits to clean it, apply a gray primer and then the spatter paint.

All of the Chevelle trunk insides have a rough finish due to the factory spatter paint. If all you want to do is clean it up and bring it back to original than just knock off the loose material, vacuum like you said, epoxy primer anything rusty, and get a couple cans of the factory spatter paint and recoat everything. A factory trunk mat will also enhance a factory appearance.

Maybe it is undercoating from a previous owner

Could be bed liner spray, many people use that for trunks and it can have a rough, almost dry sprayed appearance depending on how you apply it. There is a restoration shop here in town that sprays the trunk, the floor pan and everything underneath with that and I'm sure it's very durable. I'd say it's durable enough to be a pain to remove too.

Buy the clear that goes over the spatter paint. I believe the spatter paint is some sort of water base and soft.