Negative Height Valve Spring Retainers

I don’t recall on that set, but it would have been minimal.
In the past when I was building some circle track engines, the springs we were running needed pretty tall installed heights, and I was cutting the spring pockets .050-.060” deeper.
May not have been the wisest plan, but never had one break through.

There were a few places on the ones I’m doing that now needed .015” to get the intakes evened out, as well as the exhaust evened out.
I was looking for 1.700”, and with no shims or cups the intakes were about 1.790”, and the exhaust 1.775”.
They’re getting dual springs so the heads needed to be cut anyway.
The .060” cup and one shim under it will put me right at 1.700”.