What important differences do YOU see between the 3 different heads in the following images and why do you find them important?
Image A - Toyota 16v 4AGE head image courtesy of Bill Sherwood (www.billzilla.org)
Image B - Honda F20C cut-away image courtesy of www.carthrottle.com
Image C - Toyota 20v 4AGE head image courtesy of Bill Sherwood (www.billzilla.org)
Image D - Toyota 7AFE cut-away from the FSM
What I already see is the intake port to valve angle in the 16v head (image A) compared to that of the F20C (image B). The F20's is closer to that of Toyota's 20v (image C) runner to valve angle. You can better see this similarity by super-imposing either head on top of each other and lining up the floor of their inlet runners. The similarities with the F20C head becomes more noticeable when they're overlayed. You'll see this same design improvement with the 4/7AFE heads in 1993 (image D). In contrast, the older 4AG 16v inlet requires the intake pulses to still round a corner while "bumping" into a good portion of the valve guide. Though it's a radius-ed corner, it's not a "high-speed corner".