I've read replies to improving top-end speed by changing out transmission with OD to changing out rear-end gears. Through the help and wisdom of this forum, I've come to find-out I'm running a RPO 235 engine out of a 1949 4000 series engine. My interest is to find the most practical solution to increasing top-end from current 45 mph-ish, to having the ability to drive at 55-60 mph. Not looking for high performance speed, just practical and modest highway speeds to stretch my occasional travel distance options. My current engine isn't far from needing re-build. Stay with the 235 and rebuild plus rear-end gear change ... and/or find a 5 speed OD transmission. Thanks in advance of the worldly advice from the Stovebolt members.
