360 and 352 have a 3.50 inch stroke, so the dowel or wire will move about that much, depending on how straight you can keep it.

The 390 has a 3.784 stroke, so look for just over 3 3/4" of movement.

http://www.clubfte.com/users/ratsmoker/FAQ.html

Car 390s became almost the "standard" engine in '66 (in full size cars--Galaxie and Mercury full size) with the advent of the "Regular Fuel" 390 2v. The last year of the 352 was '67. So from '68 on, mostly you'll find 390s in cars. (427s and 428s were rare and more prone to being blowed up....) Some in Mustangs, Cougars, Fairlanes and Comets, but again the blow up/wrecked rule applies to those vs. the more conservatively owned and driven full size 4 door sedans and wagons.

In pickups, mostly you'll find 360s starting in '68. No 390s in 4x4s, but tons of FE motors up until the end of '74. So, measure away.....