I would NOT put Panchito heads on a 1776 that doesn't make power above 6,000 rpm. The small gain you'll get in the top rpm's doesn't justify the loss of airspeed (and fuel dropping out of the mix) through the intake ports the engine will experience in the lower part of the powerband. This loss will translate into an ever so slightly soggier bottom end/ low midrange (where we do 95 or 97% of our driving), which you may or may not even really feel, but the resulting (albeit probably small) mileage loss will tell you the combo isn't optimal.
On the contrary: the Panchos are designed to make more air speed through the intake ports. That's their whole schtick: you get high flow numbers at high RPM and, unlike a BugPack 044 or similar, high velocity at the low end so you don't lose low and midrange torque.
Not saying it makes sense to upgrade this engine at this time but the Panchos, if they perform as advertised, would not cause a soggy bottom. Quite to the contrary.
As for what you have now... I don't know, and Shoptalk forums are probably even less expert than us knuckleheads, but here's one guy's post on that subject.
This is the MFG page for what you have.