Red Headed Stepchild-75 Swinger LSX Swap

TT5.9mag said
You gotta be careful with transition length. I read some testing years ago by Corky Bell that said something to the effect of double the diameter of the larger pipe in length is the minimum. So for a 4” to 3” transition you’d want to use 8” of length minimum to do it or it’s a power looser. I hope I’m remembering that correctly. I’ll see if I can find where he said and tested it.

I definitely don't have 8 inches to do the transition at any point, especially at the throttle body/intercooler. So I'll have to take the hit where applicable. But these newer turbos make more power and make it earlier than the old setup, so I should be fine with the hit.