What may be an issue is that the original 229 distributor has a vacuum advance in addition to the mechanical advance. Assuming the vacuum advance receives manifold vacuum (vacuum rises as throttle closes), then this is would aid fuel economy and emissions. If one disregards the vacuum advance, then curve 'A' on the 123 distributor is virtually identical to the mechanical curve of the 229.
If the vacuum advance receives ported vacuum (vacuum rises as throttle opens but only til about half throttle), then 123 distributor curve '5' or 'E' may be more suitable.
If the vacuum advance receives ported vacuum (vacuum rises as throttle opens but only til about half throttle), then 123 distributor curve '5' or 'E' may be more suitable.
