I recently put my chevy rebuilt 327/ turbo 350 together and fired it up for the first time. Everything seems to be fine , no ordinay noises or leaks. I attempted to put the tranie into gear( with no driveline atteched just a temprary short shaft to keep trani fluid from leaking.) but couldnt get the shaft to rotate. It rotate for a while during reverse was ingauged. I pulled on the kickdown cable which is usually atech to the carb linkage. What am i doing wrong.