Front track width

The AMA and MVMA specs show the following (I believe the governing body name changed, but the charts appear to match):

1964 Valiant tread - 55.9 front, 55.6 rear
1974 Valiant tread - 59.1 front, 55.4 rear

Note that wheels probably affect this some, as does the possible additional width due to disk brakes available on the 1974 model.

I narrowed a later k-frame to fit an earlier a-body years ago and I think I cut 2.5" out of the middle of it. Afterwards, I figured out somehow that it should have been 2.4", IIRC. Might have been some frame dimensions I found later. Thread should be on slant6.org if anyone cared to look. Still have the stupid thing (car was too rusty to save).