Talk to J.R. Adkins, he has some of the best turbo's out there. He has a new Schwitzer that spools like an HY-9 but puts out more air than an HX-40. This turbo would work awesome with your mach 2's and be good for towing. You can reach him at 317-281-3130.

 

Yes i measured my own backpressure and at 45psi and under is is 1to1 or a little less and at 53psi it measure 58psi of back pressure. In comparison to the two b-1s i have owned this htb2 is far better in ever way.