What your really doing here is compareing apple and oranges.

Diesel conversions are set up to use glow fuel so their port timing is for glow fuel.
Engines that are made to run on diesel have their timing to benifit running.

A tuned pipe for glow shouldn't do well on diesel ... Different port timing.

Some where some body has already been here and done this.
Not just speckulated about it. Where is DDD when you need him?