Thanks guys for the education.
The model was no doubt faster on it's last flight <with the tuned pipe vs without it>. On the ground it spun a 10x7 @ 14,500 RPM after trimming the length down some. Best it did before was 13,400 <same prop/nitro ect> However with some elevator linkage issues it was akin to a tiger chasing it's tail at some points. So when the throttle was slow to respond <close> and the wacky elevator I landed. I had some suspicion that the flight pack might have been low. So much for that thought.
Have to finish the elevator linkage mod, and put some more time on the model.
Tommy
<P.S. I like the bit about it's a "feature">