If you've never owned an LS1 or LT1 F-Body then you're in no place to talk about what abuse they will stand up to, how long they will last, what goes wrong with them at what mileage, and so on. I have owned these cars, and also several Mustangs before the F-Bodies. I also sold new Chevrolets for a stint in 2002, so I got to see all of them come through the service department each day.... I spent years running around Dallas/Ft. Worth area with all the local members of LS1.com, and I swear to god if I had $10 for everytime an LS1 bent pushrods I'd have enough cash to buy myself a new KB 1.7 right now. My last F-Body had over 100K miles on the clock and that motor was so worn out its pathetic. Mustangs will last two times as long as any F-Body, and not cost you an arm and a leg to keep it running. $300 to replace the water-pump...$350 to replace the distributor... give me a break!
My best friend of 15 years ordered and waited three months for his 99 TransAM to have the weak a$$ valve-train crumple when the motor had just under 1000 miles on it. Valve-marks on the pistons and the works. GM replaced the entire motor in his car and then voided his power-train warranty on a brand new f-ing car. I don't care how much anyone tries to stick up for the LS1, any motor that breaks as easily as those do should not ever even be put into a car to be sold to the public. And then Pontiac has the nerve to advertise the TransAM Smoking the tires on Daytona Speedway in the vehicle product-brochure. GM...What a bunch of crooks.