I don't think a semi will give the same results
But for the purest engine experience, displacement has no replacement. All other methods are simply attempts to artificially recreate the benefits of displacement.
if it still squeels, then take it off the pulleys and emery the pulley groves a bit, they probably just shinnied up over the years, it may be worth just a lite emery of the belt too as they shine up too
Just sounds like your fan belt. If it goes and your battery light comes on, DON'T drive. That' show I've just knackered my head gasket or something around there... lol.