Last year I decided to chaange my inner cam bearing, and while I was at it I decided to install a EV27 cam. I did keep the gear from the old camshaft and pressed it on the new one to eliminate any noise from the gears.
I had Rivera Taperlite adjustable pushrods in it, and after the cam change I had a lot of noise. I suspected it was the front pushrod hitting the inside of pushrod tube, due to the greater angle of the front pushrod.
I dug into it, and I documented what I did with photos and got rid of my noise. The EV27 is still a little noisier than stock, but that is pretty normal. But the heavy clacking sound is gone.
I make no claims that this will work for everyone, but it worked for me.

Here is the link to my project hope it might help someone.
http://www.capitalhosting.ca/harley/valvetrain/

 

Pioneering work there Stubby, well done! Might be a good reason for sticking with stock pushrods instead of buying adjustable ones.

 

I just replaced the cam brg. in my 99 Softail Custom, and replaced the pushrods with Screaming Eagle quick install. Guess I was lucky as I have no noise. I did not change the cam though, as mine runs so well stock. Probably just the luck of the draw on how well your pushrods fit. It is a little odd that it was not noisy before you changed the cam. Maybe the EV-27 is a little higher lift. Thanks for posting this, and you really did a good job with the pictures. I know there have been others with this problem.

 

I've run both Screamin' Eagle Pushrods and Crane pushrods. The SE rods fit fine (so long as they're straight), but the Crane rods hit the inside of the tube with the "step" in the rod for the threaded section. I fixed this by shortening the inside pushrod tube (the unplated upper tube) by about 1/16 inch to clear.

 

Great tip on using paperclips and rubber bands to hold the tubes in place. I'm right in the middle of putting in an EV27 cam, EZ install pushrods, hydraulic lifters and chrome hydraulic tappet blocks. Your article is going to be helpful in getting it done.