I have a set of factory 87 GN cylinder heads that were just refreshed and reconditioned last week for sale. The heads have the LT1 valve springs on them and they all tested between 97-102 psi spring pressure which is like brand new. The surfaces were trued and they also had a regular valve job done to them. These heads have never been ported. Like brand new! Asking $550 shipped. Please email me at d0n3d@comcast.net if interested. First come first serve basis. Do not call me at work! Thanks guys.