4 7/8 bs, with a .350 spacer on one side, .375 on the other. So, 4 1/2 could be perfect, but maybe only on my car. My 62 has a later rear-end in it, maybe 65, maybe 66/67. The 10 1/2 slicks make fit critical.
Edit: the slicks I have on the wheels at the moment will NOT fit on the barracuda. When I put the smaller e,t, streets on, those will fit. (The pics I have of the wheels are on my phone, but I'm doing this on a new tablet, no photos at all. Sorry.)
2nd edit: Mr Sinisters wheels are clearly the 3 5/16 version.