I have a J313 date with a 3782870 casting and a FII0IS suffix. I find it to be a 1964 chevelle spec. hi performance. Is that correct or not?

J313= Oct 31st 1963 casting date
3782870=327 block 62-67

F=Flint engine plant
II0I=Nov 1st engine assembly date
S= In '64 model year, 64 Impala 327/250 L-30

The 64 Chevelle SHP code is JS. (There is a Camaro site's engine info that has a typo using a small J showing it as lS)

Here is the 64 Chevelle engine code list
http://www.chevelles.com/years/64/64codes.html

Thanks for the info.