You don't have to be an engineer or an engineering student to make equal length long tube headers.
From my experience of doing a rough model in cad and actually making a log manifold turbo setup out of SH10 pipe
, I realized that it'* much easier and more practical to take a few measurements and just do it. There is too much human error when cutting, welding, the metal deforming when welding, etc. to account for in a model.
So, for my long tube headers, I got an empty block, trans case, top end, and took a few measurements of surrounding components in the engine bay. There'* no suprises there. And I don't have a need for modeling it in FE software since I found my desired dimensions analytically.