How to find 5.3 without....

Castech 706 heads?
Ok, i have a 1999 ecsb 4x4 with the 4.8. I pull a boat and it just lacks too much torque. I cant afford to get a 6.0 to swap in, everyone wants 2 to 3 times the price for a 6.0 than i can find a low mileage 5.3 for. My dilemma is finding a 5.3 that does not have those cracking 706 castech heads on it.I would probably be getting on off ebay so theres no way to know if it has them or not. Did all 2001-06 trucks and full size suv's have those heads on them? I know the L33 shouldnt have them but they want the same price for those as they do a 6.0. I know the bulletin for the 706 castechs are for 2001-06, so i COULD find a 1999-2000 5.3 to avoid the heads alltogether, BUT, those 2 years are also the lowest HP and torque engines compared to the 2001 and up, so thats defeating the purpose..lol..any help here guys?

I have the 706 heads on my 2004 5.3. The motor now has over 90000 miles and a 212/218 cam and my heads are fine. Not all 706 heads are bad. Just make sure you check the motor when you get it .

I have found a LM4 all aluminum 5.3 from a 2003 trailblazer (vin code P), could it also have the castech heads on it or is it safe?