H3 Manifolds?

[NorCalAnthony]

Has anyone tried running Hummer H3 exhaust manifolds for LSx swaps in a square body? I believe they're the same ones used in the Colorado's and Canyons with the 5.3 so they should fit in some pretty tight engine bays... I'm collecting parts for my 5.3/4l80e swap on my '89 K5 and was originally going to use the TBSS exhaust manifolds like most people do but I'm having a really hard time finding any and have heard that they may now be discontinued. These look like they may be a good factory alternative but I haven't been able to find anyone who's used them before. What do you guys think?

Here's the left/driver's side (P/N 12598548)



Here's the right/passenger's side (P/N 12600527)