Designed for 88" to 107" engines with compression ratios from 10.0:0 to 10.5:1 and 100" and 107" engines with compression ratios 9.7:1 to 10.5:1. Strongest from 3500-6000 rpm for 88" to 103" engines and 2500-5000 rpm for larger engines. Made in the USA. Installer must check coil bind, valve to valve clearance and valve to piston clearance..
