I just installed them onto my current engine in the car.
I did not know how I could make a plug, or casting or have them made.
I just lost interest after I saw the Sissell/Duggan 12 port head years before I even made these upper lumps., Always said to myself, someday I will have a 12 port aluminum head.
If anyone else would like to look into this type of mod, (upper lumps), Is say go for it & post your findings, not just head flow numbers, that's only part of a combination.
I think they would be worth looking into. Never seen anyone make them.
I did flow test my head w/the clay models installed & the flow numbers did improve. Not a huge gain mind you, but more of a gain noted in the 1/4 mile & racing against my friends street/strip cars. The improvement was most likely due because w/the upper lumps installed the port velocity went up.
The clay model I posted is more what I wanted them to look like but also wanted the long turn radius side to reach closer the the valves for a better flow path.
