I have those on my engine. They are springy. :toothy10: I had my machinist install them anyhow because he disassembled my heads after pressure testing. They work and do their job. I have that K6901 cam and the matching lifters and factory pushrods. Springs are on a set of '79 318 smog heads with bronze valve guides on a '73 318 block. It doesn't mind pulling to 4k at all or 5k.
