[LT7A]

Well weider, I don't know if you're going to come back and look at your thread, haha, but you've gotten a surprising number of responses. Nice to see that nobody is simply saying don't waste your time. A lot of people seem to think that way about the TBI motors. Everything I listed is on my daily driver. No problem with my exhaust and my research shows people have had similar results. Not sure how common the feedback EGR system is. Many like myself, have found that the cold air stock system is restrictive. I run a K&N filter with a K&N open lid *beware, controversial* but I bought that before the filter tests had come out that show that K&N lets more dirt through than some others. My truck was just a few years old when I put that filter on and so I would say that the 230,000 miles indicates that it's not letting too much extra dirt in, haha. No need to spring for that, but per my experience and others, you will feel the seat of the pants improvement if you swap in the open element air cleaner. If you've opened up the exhaust, then it'll want to breathe. The volume of air available with an open element more than offsets the warmer underhood temperature it's drawing from. Cool air is a plus, but the open element is far better than breathing through the factory snorkel. Pre ignition or pinging has never been a problem for my truck - in fact it's common to advance the timing up to 6°. I run 4° advanced, have towed a 33-ft travel trailer that way, on 87 octane with no pinging. I like the roller cam idea for durability and since you're going to be into the motor. Just don't expect much in the way of power gains. I do agree that you can't change the cam profile without a chip telling the ECU how to deal with it. The reduced friction of a roller cam will net a small gain. I have had no problem with my flat tappet cam, but depending on how you take care of it they are susceptible to wear with today's common oils. I like to run amsoil that takes my flat tappet cam into account but if I was doing a rebuild would probably go roller. Big question is, do you need to go into your motor at all, and if so, why? Sounds like your heads need minor attention, but is there a problem in the motor itself?
In real world driving, my truck is far more responsive than when it was new. Weighs 5,000 lb and has a 3.73 rear axle. Would not break the 265 75 16s loose when new, but makes the 285 75 16 BFG ATs howl now from a standing start, despite the age and mileage.