Ford pintoNoise....plus that while the heads were off for the rebuild, my friend who normally spends his time fettling ford pinto race engines took a die grinder and flap wheel to the valve ports and gave her a "little" bit more flow
i tried a straight pipe on it years ago, it sounds more like the engine in a spitfire fighter when it was at full chat...and i couldnt hear that rather soft spreaking woman on radio 4, what ever her name is...
We're these valves opened up when you did the comparison with the 956