For what it's worth, I have 850 w/stainless muffs and tips on the Vette, took him 5 hours. 350 on the Mustang w/aluminum muff, 250 cat back w/stainless muff on the DD 4x4 and 800 on the Harley. Have not done the Plymouth yet, but I'm guessing 1000.....But hey, I'm a freak...