Crank

Just to help: 1964-69 273 crank Stroke 3.310" con. Rod Journal 2.1240-2.1250 Main Brg. Journal 2.4995-2.5005
1968-71 340 crank Stroke 3.310" con. Rod Journal 2.1240-2.1250 Main Brg. Journal 2.4995-2.5005

So, yes, this 273 crank will fit in a 340. Found this info in an old GLENN's TUNE-UP AND REPAIR GUIDE I PICKED UP AT A TAG SALE.