Valve springs: Everytime you exceed about 5000rpm, the stock springs get in big trouble with any cam that is bigger than a C grind. Dual springs or Beehive's will increase the life of your valves, valve seats, cam, lifters & every other part of your valve train.

Pistons: KS are a bit dodgey, but genuine Mahle pistons are fine to 6500 with the occasional 7000 rpm excursion.

Head: In Australia, B20A/B/E heads from 1973 onwards have the slightly raised exhaust port SSR which is easily modified for reasonable flow. The E valves have a stellite face, but you still need hardend seat insert to run on unleaded fuel for extended periods of full throttle.

2x 40mm: They are enough for 150HP maximum. If you don't own them, then don't bother buying a pair. If you do own them, I'd use them as throttle bodies for MegaSquirt, as you could probably bore them out to 48mm.




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Three 164's, Two 144's, One 142 & a partridge in a pear tree.