How 'bolt-on" would a swap to a 6-speed from another GM product be?

 

You'd have to be more specific. What engine/trans? You could end up with something that will physically bolt up(engine to trans), but you would have compatibility issues with mounts, electronics, axles, hubs, and the list goes on. In short its likely not worth it.

 

From what I remember, the reason the HHR in later years didn't get the 6 speed, it didn't fit.

 

Welcome to the forum Jim. How "bolt on"? How about "not bolt on". Sorry but the results wouldn't be worth the work and many $'s it would take.

 

I was thinking about this also but when I looked at the gear ratios the over drive ratio is the same. The gears between 1&5 are spaced out more but 6th is the same ratio as our 4th.