An intriguing development...
 

Today I fitted 98 Subaru WRX valves, springs, retainers, collets and buckets to my spare head...fitted fine. Camshafts will require modification as they sit higher than before, but it makes for an easier regrind opportunity as the base circle needs to be reduced.

Meaning, max lift on the standard springs is increased from the 9mm (ish) of before to 10.91mm. However, the buckets are shim over and STI Ver 3 WRX's are shim under and are the same bucket diameter.

Therefore with this valve setup, 10.5mm lift is possible without expensive modifications.

Food for thought.

Matt

I believe that set up requires reducing the base circle of the cam too much. Look at the cams. You not only will be cutting into the fillets you'd be cutting right past them and into the cams.

The buckets I used were the shim over type.

If we used the shim under type, on the smallest height, with the valve tip ground down, it wouldn't be eating into the base circle too much. The difference is about 2mm.

Who's tried it before? I asked this question ages ago, and nobody knew the answer.

M