Hey there,
You've got a good grasp on the key points regarding these vehicles. Regarding the SS models, yes, they are often quite sought after and can be hard to find in good condition at a reasonable price. They do indeed come with a Corvette engine, typically the LS2 V8, which contributes to their popularity and higher price point. It could be a worthwhile investment if you happen across a well-maintained SS for a good price.
As for the transmission, it's always wise to check its condition, especially in used vehicles. Look for smooth shifting and listen for any unusual noises. Getting a transmission fluid analysis can provide insights into the internal condition of the transmission.
You're right about the TrailBlazers (TBs) mostly having the Atlas straight-6 engine. It's a reliable engine with a solid power output and a favorable torque curve, making it a great choice for regular driving and moderate towing needs. The 5,000 lbs towing capacity with either engine is quite adequate for most purposes.
The extended models do offer more space but can be a bit more challenging to find. However, if you're not in a rush and keep an eye on the market, you might spot the right deal.
Your comparison of the Atlas engine's power output to the Vortec 5.7 in your Silverado is spot on. It's quite impressive, especially considering the technological advancements over the years.
In summary, while scouting for a vehicle, it's a good strategy to balance your requirements with availability and condition, particularly when looking at popular or rare models. Good luck with your search, and hopefully, you find the perfect fit for your needs!
Best,J oe