The 70's era spacing measures 4" from center to center of the pickups. The 60's era and post 70's era use the standard 3.6" spacing. My 1965 Jazz that I bought in 1966 had the 3.6" 60's spacing and my 1982 Jazz that I bought in 1985 has the 4" spacing. My '82 also has an all-maple neck whereas my '65 was maple with a rosewood fingerboard. My '82 has a little brighter sound primarily because the bridge pickup is closer to the bridge. It also has far more sustain than my '65 did but a fair amount of that might be because of the all-maple neck. My '82 also growls easier than my '65 did.I've seen posts like that before . . . is pre-70s and post-70s the same spacing?
Here's a pick of both 60's and 70's spacing side by side the one on the right is my '82 Jazz with the 70's spacing. There's less than 1/2" difference but being 0.4" closer to the bridge is easily visible and it makes a noticeable difference in the sound.

