ORIGINAL: w8ye
Being as you already have the parts, try it in the manner you described. Typically the pipe would not need to be cut. You may need to lengthen it a little?
It will help a little. The greatest effective gain of the pipe would be at higher rpms though.
How does higher rpm relate to the greatest effective gain of the pipe?
Attached is what we did with a tuned pipe to bring the peak power from 17k to 10.5k rpm look at that huge gain in power at that 10.5k rpm point, from 1.4 hp to about 1.72 hp. It is almost back up to the same power it had at the 17k rpm point. This was for an 10cc FAI F3A Pattern engine.