I have'nt played the " new " '70's Fenders, but I had one of the actual '70's Jazzes, and it had a very chunky neck, and weighed close to 9.75 lbs. Back pain city. As soon as I bought a new Jazz, the back pain went away. Don't know if the new '70's weigh that much. Also, that half inch closer to the bridge makes alot of tonal difference, imho.
R.I.P Duck Dunn, 2012.