<html class="apple-mail-supports-explicit-dark-mode"><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto">Good evening all,<div>I have always run regular 87 octane in my TR3(‘66 TR4 motor), no knocks or pings. Don’t know what got me to thinking but there has to be a relation between compression psi and the octane rating I should use. My compression across all four is 175-180, would I be getting improved performance from a higher octane gas? Or just wasting $$ ?<div>All the best,</div><div>Bill B</div><div>TS30766L<br><div><br id="lineBreakAtBeginningOfSignature"><div dir="ltr">“The harder I work, the luckier I get<span style="font-size: 19pt;">” H. Ford</span></div></div></div></div></body></html>