jdoclogan
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With Roy Stetina's #21 in my shop and some of the racing components from the 60s when Stetina raced. I was amazed at the following head modifications.
First off I did a Vizard modification (for #41 Sebring Alpine) taken from standard drawings that I shared here before. My grinding process ended with approximately 41cc of material removal per cylinder and somewhat vertical walls. In addition I ground and polished from the manifold side all of the inlet and exhaust channels.
The first Stetina head I found had a Vizard modification with more of a sloping grind out to a slightly increased perimeter. It also had ground and polished inlet and exhaust channels from the manifold and block side of the head. Note: water jacket preparation before head machining.
Then I find a significantly different modified head that came from the dozen or so heads I obtained. The machinist took the grinding all the way to the inside edge of the piston perimeter. It was sloped as well. Both the inlet and exhaust channels were ground and polished from the manifold and piston side. This made for a significant molecular flow increase. I'm thinking this was to accommodate a domed piston.
I would welcome any comments.
First off I did a Vizard modification (for #41 Sebring Alpine) taken from standard drawings that I shared here before. My grinding process ended with approximately 41cc of material removal per cylinder and somewhat vertical walls. In addition I ground and polished from the manifold side all of the inlet and exhaust channels.
The first Stetina head I found had a Vizard modification with more of a sloping grind out to a slightly increased perimeter. It also had ground and polished inlet and exhaust channels from the manifold and block side of the head. Note: water jacket preparation before head machining.
Then I find a significantly different modified head that came from the dozen or so heads I obtained. The machinist took the grinding all the way to the inside edge of the piston perimeter. It was sloped as well. Both the inlet and exhaust channels were ground and polished from the manifold and piston side. This made for a significant molecular flow increase. I'm thinking this was to accommodate a domed piston.
I would welcome any comments.
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