Sounds like the arm is on top of the cam lobe istead of under it.
The resistance you feel depends on the position of the cam. You a good light and an inspection mirror you may be able to see the lobe. It's a common error that nearly everyone has made I think.


1953 Chevy 5-window 3100
In the Stovebolt Gallery
More pix on Picturetrail

Dave
Engine & Driveline Moderator

If you can't make seventy by an easy road, don't go. ~~ Mark Twain