Mo power for my Mopar 340...

No problem!

The RPM will be fine, I like the new design of the air gap but if you've already got the regular RPM I'd keep it. The cam specs will be the biggest issue going to the 1.6's, if its already a higher lift cam with the stock heads you could max out the lift pretty easily.

Most manufacturers stamp the cams too, so if you felt like pulling the timing cover you might be able to get the info that way.