I was playing with my parts in the garage a little while ago (truck parts - come on people) and I decided to document the differences between the stock heads and the Stage IIs I'll be putting on. So here that is...
Cams - I was surprised that I could actually easily see the increased duration in the cam grind. These pics are crappy, but what you're looking for is the overall shape of the lobe, especially the narrow part on top. The narrower this peak is, the quicker the valve event. Slower event = valve open longer = more duration. I could also see a slight increase in lift as observed by the taller narrow part on the new cam, but it is a small difference.
Stock cam lobe:
Stage II cam lobe:
Here are the combustion chambers compared...
Stock:
and Stage II:
and the valves with a tape for reference...
Stock:
and Stage II:
Here are the ports, intake first, with the gasket for reference...
Stock:
and Stage II:
and finally, the exhaust ports, with a tape for reference...
Stock (note that the port is actually about 1-1/4" across - the carbon build up makes it look larger):
and Stage II:
Sorry about the book (but hey it's a picture book), but I thought this might be good info for anyone considering heads, but not really sure of what they'll get.
Enjoy,
Herb
Cams - I was surprised that I could actually easily see the increased duration in the cam grind. These pics are crappy, but what you're looking for is the overall shape of the lobe, especially the narrow part on top. The narrower this peak is, the quicker the valve event. Slower event = valve open longer = more duration. I could also see a slight increase in lift as observed by the taller narrow part on the new cam, but it is a small difference.
Stock cam lobe:
Stage II cam lobe:
Here are the combustion chambers compared...
Stock:
and Stage II:
and the valves with a tape for reference...
Stock:
and Stage II:
Here are the ports, intake first, with the gasket for reference...
Stock:
and Stage II:
and finally, the exhaust ports, with a tape for reference...
Stock (note that the port is actually about 1-1/4" across - the carbon build up makes it look larger):
and Stage II:
Sorry about the book (but hey it's a picture book), but I thought this might be good info for anyone considering heads, but not really sure of what they'll get.
Enjoy,
Herb
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