Maybe I'm missing something, but if the pilot of the converter measures 1.55" then it is for the early 62-67, 904 transmission, and I take it that you are going to use the early 904 transmission and converter you now have behind the 340. The 340 will have as mentioned earlier, a larger hole in the crankshaft, probably around 1.810". I know that there is a bushing available that you can install in the crank. It is a cheap, fix, and in my opinion NOT the way to go. In your Province there is a company called SMR in Bradford, 1-888-846-6603 that can correct the issue by rebuilding the 904 converter you have now, and will put the correct pilot put on it. The company I worked for in the past did a fair number of these and never had any complaints. If it were me, I'd talk to SMR, tell them what I've got, and what I planned on doing. Again, jmho. Best of luck. Do it right ONCE.