Our competition-quality valves are constructed of forged EN24N stainless steel, with chrome plated stem and stellite tip. They are high-flow thin profile with waisted stems. All take single groove keeper. Long-stem valves for 1275 12G940 and 12G1316 cylinder heads. These valves require matching keepers, see 88G0459. Sold each.
For race applications, consider SEN0449 valve, which has slimmer neck.
Verify which type of valve tip you need, see comparison picture.