I love both of those strains separately. They are actually among my favorites. But I can for sure understand why they wouldn't be ideal together. Jack is more cerebral while SourD is more body.

I would like to combine Jack Herer with my other favorite strain Headband, I imagine that would create a creativity stimulating heady high. Headband is a child of Sour D and OG Kush, so it could end up very similar to Jack Diesel.