Valve Springs

TECHNICAL NOTE
On some Early small block Olds heads (casting # 1, 2, 3, 4 & some 5) the installed spring height is very short, usually 1.600″, and in many cases the spring seats need to be machined up to .090″ to achieve proper installed spring height. This may also happen on some Olds big block heads #A, B & C. The Olds small block 7 and 7A heads and some big block “G” heads usually are 1/2 deep & 1/2 shallow. If so, specify or machine heads to all deep spring seats.
(Shallow spring seat heads do not have valve spring rotators while deep spring seat heads do. Be sure to check your heads closely.)