don't ya have to install larger valves in a 20 r head to make the swap worthwile ? ![Think... :think:](https://board.marlincrawler.com/Smileys/marlin/think.gif)
running stock 22R valves in the 20R head make for LOTS more power, but taking a stock 20R head and sitting it on a 1980-1984 "tall" 22R block will push that 22R from 105 hp to 135 easy