After the modified the head yeh i polished up the groove with fine wet sandpaper then used aluminium polish and then finally cleaned it off with fuel.

the engine was a missile in the 3 qualifiers going down the straight but the punch out of the corners was not there so were trying to tune a better low end. then we found the clutch to be not set correctly.

i gues when the first plug blew we didnt open the engine then to remove the plug wire, i guess this is what caused the second plug to blow and kill the engine

i was still using the standard shim setup under the head. when creating this scoop is it best to add or remove a shim ?