I'm building a 800imp stock for grass racing next year either a grand touring or longtracking a mach z to a 136".Has anyone dyoed race pipes against each other who put out more torque and hp.Thank's

Go with either Crank Shop or Jaws, both work great for running on the grass. I perfer the Crank Shop because they run at a lower RPM and are easier to tune on. My sled Dyno's at 200hp with the CrankShop pipes at 9200 rpms. (800 IMP)