Oh, and to put that weight into perspective, the stripped down '57 Porsche 356 Speedster weighed 794kg's.
I am planning to upgrade my existing engine in situ for a bit more power. I'll be replacing the cam later today with one from a Mk2 Vitesse, which should give me another 6 or 7 hp. I'll see how that affects performance then add in a pair of 1.75" Strombergs that are sitting in the garage for maybe another 6 or 7hp, followed by a Witor flow balanced manifold for perhaps another 10. The chap who dyno'd it for me also recommended bypassing the inlet manifold heating pipe for a couple of hp. If I end up with 100bhp I'll be happy, but more would be better.