Are your 'clunks' coming from a particular side?
On a different note - I did the exhaust fix. It actually was simple (I think I'll tackle an enegine rebuild next

). I did notice more response in lower RPMs although there still is a noticable demarcation at 2900 rpm where it just seems to open up and rip. I figure the freer exhaust smoothed it out a little but why the noticable power jump at 2900+ in the first place?