I have a 99 chevy k2500 suburban with a 7.4 liter engine. I had a tune-up two weeks ago, all was good. the next day I got a muffler put on, the guy said I didn't need dual mufflers, it was a waste of mufflers, and that I only needed a single muffler and single pipe. Well, after that I felt the truck was limited on power and acceleration. I could not pass or accelerate up hills. I took it up hwy 80 to Truckee and on the big hills it had no acceleration at all, When I got to Truckee I pulled off and listened and heard some unsettling noises from the engine. Took it to a shop, (4th of July weekend, no one open!) a 76 station was open everyday, they looked at it the next morning and said the engine is blown and I need a new engine. I was upset. I towed it to another place that I knew and trusted, they said the same thing. but they also said, "this muffler system is too small for this engine, this could have caused the damage." And other shops have agreed. Do I have a case?