Jay wrote:
>Someone asked me the size of my Holbay head intake inlet size. That is,
>the size it was opened up to to match the 40 DCOE side draft Webers. I
>can't find that e-mail. Sorry. So, everyone gets the number. I measured
>it at 32.7 mm in diameter.
The 32.7mm runner diameter is quite large. I doubt the stock holbay head
had such large runners, becuase this was contradictive to the strategy that
Holbay was after in the tuning of the H120 engine. The strategy seems to
have been to keep the port velocities high, and utilize the valve-train
reversion to give higher volumetric efficiencies as lower RPMs.
Larger ports are great at higher RPMs, but probably not so good for the
camming strategy from the H120 cam.
It is my understanding that the stock H120 head used slightly smaller
exhaust ports, and the same sized intakes as compared to stock.
Jarrid Gross
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