Hi guys, would like to enquire about how to actually differentiate which one is redtop and which one is bluetop for the 16v versions of the 4A-GE? There's also another term whereby it's big port and small port, it really gets me blur about it. Kindly would like to know how to differentiate, and also from which series of chassis does these engine comes from? As i'm looking for a 16v big port cylinder head for some research purposes :D