Not sure what they made in 1964, I was 9 years old at the time and really don't remember........
The 157 tooth flywheel is for a 10 to 10.5clutch disc, the 164 tooth flywheel uses an 11 inch clutch andwas mainly used on trucks like the F-250....not sure when they began making the 164/11 inch stuff,but I've seen some from the mid 70's........
Just a WAG,I'd say in 1964 on a 289,it wuld be the 157 tooth flywheel........
David