Thanks Marc, hence the nickname the Professor. I bought this new digital protractor and did not zero the trailer as I was told by Goldman. I read 0.5 degrees on both flanges thinking I was golden, however after your post I got to thinking maybe it is .05 each way.....(there are arrows on the protractor that tell you this, dumb me) this time I zeroed the transom flange and now the Bam 1500 transmission flange is off 1 degree. Also did another measurement with the bar stock clamped on each side of the flange this time and another bad reading. with 24" of bar stock horizontally it is off 3/32" or half that distance to true it up. 15 1/2" one side and 15 19/32" the other. I think having the two clamps on the flanges gave a better reading. Time to move the engine. Thank you all for the help.

I run 1410 u-joints on 1480 flanges (why that is I am not sure)and they are breaking at the transmission side at the yoke not the u-joint. I am having 1480's made this time. The u-joint becomes a mess after the yoke breaks. No vibration at all. Just a loud racket when it lets go. This time the wife was screaming at me to shut it off, shut it off. However at 100 mph the prop keeps the broken shaft spinning and chewing up the prop shaft cover.

Brad,

Here is a very quick and dirty sketch. You know what they say about a picture

Once you zero the level on the transom flange whatever angle exists now becomes the reference (bottom of level).

It is important to use the opposite surface of the level against the transmission flange (top of level).

Make sense?

This is very confusing on a good day.

1480 will help

Glad to see you are finding the cause. Hate to see you break, I know the frustration!!