gear ratio swap

If you are going to run an old Fairbanks 3000 stall converter against those steep gears, it's going to raise your transmission temperature and have lots of inefficiency at cruise.

Modern torque converters are much better designs and my recommendation would be to contact Precision or another quality torque converter company and get their recommendation. The new style converters are dramatically more efficient than they were even 15 years ago.

Sure it's an extra $400, but the car will run and perform better without cooking your trans. You should also run an additional cooler after it goes through the radiator and perhaps a deep pan.