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I expeimented with cams in the 8 valve head, and the results are quite suprising...
I never bothered doing it to the 12v as there are a few other things that will stop it from revving out:
1. longer stroke than the SOHC FE
2. use of hydraulic valve gear (HLAs) rather than solid
Plus I wanted to keep the torque as low down as it is now in the rev range, as its a DD primarily
On the 8v I used a 26/66 (stock is 14/58 or 20/65 depending on the engine)
there was a noticeable increase in torque and it felt more consistent across the rev range (seat of the pants dyno)
However I had to advance the cam about 6 degrees to make it like that.
It started out with the torque very peaky and high up at the factory cam wheel position, which was useless in a road car, and made it slower to drive in outright terms.
thankfully the 8 valve head, you can install the cam sprocket 3 ways for slight variations in timing
I tried it at all three different spots, plus one tooth either side of each spot, 9 different postions in all...so I did plenty of testing...and settled on postion "C" instead of position "A". Each time I tried some different combinations of spark advance in each position, so it worked out to be about 20 different combos to test.
Now, I dont know if any of that info will translate that well to the 12v, although the 12v flows only a little bit better than the 8 valve....
Except to say you'd want to have a vernier cam wheel to make good use of whatever cam you end up using....otherwise there is a danger that the torque curve will narrow, and it'll be a pig to drive fast.
Also if you have to pass any kind of emissions test, forget changing your cam, extending the duration will increase the overlap and your HC emissions will increase by a large margin.
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