Here's a way to give your Shovelhead engine the nostalgic look of a Pan, and improve the performance at the same time The P-Series heads are the same heads that come on the new P-Series engines but with a Shovelhead bolt pattern to make them compatible with any stock or aftermarket cylinder for a 1966-84 Big Twin They are also designed to accept stock or S&S o-ring style manifolds and accept any Shovelhead exhaust Heads come complete with valves and .590" lift valve springs Includes billet tappet guides and Quicke push rods and are set up to oil the top end through the push rods For 3-5/8" bore cylinders Generator crank cases it is recommended to use 725-153 or 725-154 camshafts Alternator crank cases it is recommended to use 725-157, 432-634, 432-635, or 432-637