Working on finishing some motor work and I have been following the manual and have gotten stuck. I have the cams back in and everything seems to be going smooth and all timing marks line up. After I installed the tensioner, the manual says to turn the motor over several times and this is where I am running into issues. When I try to turn it by hand, a socket with 18" breaker bar will barely turn it. I can get it to go all the way around, turned it several times, and the marks line back up but I am thinking it shouldn't be that difficult to turn by hand. Just looking for some reassurance before I disassemble to look for something I missed. Any suggestions?