'76 Small Stone volume drop

[ThisBrian]

I have a '76 Small Stone that I'd like clear up the volume drop problem on. I true bypassed it and that made me like it quite a bit more, and I think if I can get rid of the volume drop I'll keep it around. The problem is all the solutions like the one at GGG are for the later issue. Looking at the schematic it's clearly different than what I have (there are 6 ICs instead of 5). Anyone know what to change out to fix the problem on the older ones. I'd also be interested in increasing the headroom if that's possible. http://www.generalguitargadgets.com/v2/index.php?option=displaypage&Itemid=139&op=page&SubMenu=

Thanks.