my 244 kit came with double springs.

ive got double vavle springs on my ported gt spec head allready luckly

I don't only sell the cams I use them in customer engines and with the counless number I've fitted I can say in my experience they don't make power beyond 6500, they are all dynoed on the same dyno with the same tacho.

Some reasons they don't power beyond 6500 are:
duration too short.
Lobe seperation angle too tight.

Some reasons why people may think they work beyond 6500:
chokes too big.
ports too big.
tacho doesn't read correct.

I don't use this cam in competition engines as it's too tame and the cams above it will make more top end with similar torque.

Why rev it that hard if you don't need to?

I do like the 244 cam and will continue to use it in my Rally cars. I'm happy with the way I've set it up and how it makes the power. This little Kent engine has stirred up a few at the rs forum too ... seems there are tricks to be had that only a few are unaware of.