[Capri306]

UPDATE: The XE274HR showed no improvement whatsoever over any of the forementioned camshafts, at least on my simulation. In fact, the shape of the torque curve is like the E303, but about 5% LOWER across the entire band.

See the attachment.

Again, it's hard to tell for sure without knowing the exact profile of the camshaft, but I think my simulations have shown the limits for unported GT40P heads. A cleanup of the ports may well be justified; I will attempt to find reliable flow numbers and try the simulation again. Stay tuned.