Re: Piston to head clearancing
I do this just to see if I cam make it better, and improve preformance and econmy.. Most aftermarket heads add material to the transfer area ti increas compression. Then we relieve the block to improve flow. YET! The transfer area controls flow. I ran a flow bench teat on the angle of the transfer area and found a 10/12 degree angle provided the beat flow. However there isn't enough material there to t remove much. It would also reduce compression.
I only take about .010" over the dome area of the head. The rest comes off the valve area. The clearance the area over the valves at a 4 degree angle with matches the angle of the valves.. Now this depends on the lift of the cam. now removing more material from an *ba style head, material should only be removed from the block sursurface of the head as the uppre portion is very thin..
Last but not least the aftermarket heads are very expensive and only have an aesthetic value.
Gramps
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