5 port non-x-flow
We modify aluminium 5 port heads to the following levels of tuning;
Fast Road....using 1.625" inlet valves.
Big Valve Fast Road...using 1.67" inlet valves.
Rally/Race.....using 1.72" inlet valves.
All of the above specifications offer substantial power improvements over
the 'standard' item!
Derrington/HRG and X-flow 7 port heads
Although initially expensive to purchase, the 7 port configuration offers
unsurpassed mid range power.
We have over 15 years experience of developing and modifying the X-flow heads.
Heads are modified to the same specs as the 5 port heads and power improvements
are just as substantial!