The 5.3 in my Tahoe **** the bed at 268,000. I had a '99 Ls1 with 241 heads layin around so i put it in. It moves out pretty good but my low end torque sucks. I towed my 24' enclosed loaded with my Trans am (8,000 ish lbs) and it did really well. However it really needs bit more down low.

I was going to put headers and exhaust.....plus a set of 243 heads with a "towing" cam. I am unsure how big or small of a cam to run....plus if it is even worth investing in a set of 243's.