Check here. This is a close as you may come for free: http://acoustic360.homeunix.net/schematics.html Not the exact model, but possibly fairly close. Edit: acc to the site the 271 is the guitar 270 head and cab bottom combo: You may be very close with the 370 schematic, the guitar head also has fuzz controls, and such as noted.
The power amp for the 270 and 370 are identical...except the 270 didn't employ the AGC (automatic gain control) circuit (the part at the bottom with the FET in it...IIRC) that the 370 had. I confirmed this a while back with Steve Rabe (Acoustic/AMP/SWR/Raven Labs)... What's acting up, preamp or power amp? Side note...can you imagine how painful it would be to stand within earshot of a cranked up 271 with the fuzz engaged? Those horns would tear your eardrums out!!!!