olds 307 and 403

The Felpro head gaskets are somewhere between .039" to .041" compressed, yes they do compression some. A new set of Edelbrock Performer springs are cheap, since they are going to the shop. I got lucky on my #6 heads, fully rebuilt for $400, supposedly $1200 it in, they were good. Sometimes the work done is subpar, just the way it goes.