two of our guys have stroked FEs. One with a 3550 .64 od, Jag 3:54 and the other TKO 500 .64 od with 3:25 gears. They cruise at 1900 to 2100 rpms in 5th gear. If they drop 200 rpms they have to down shift.
I have a 302 stroked to 354, TKO 600 .64 od 3:55 gears and small tires 25 1/4". I can cruise 1300 to 1500 in 5th. At 70 I'm doing 2000. Each motor/car is different. Do the math and then buy the parts, then change it if it does not perfort the way you want it to.
That's what I done for the last seven years. But I'm there
Dwight