Sorry for the long post in advance-
MY truck is a 63' with a 301, Isky E-4, 4v Eddlebrock, headers, ported heads, rebuilt stock Cruise O Matic.
Tires are 255/70R15's or 29.1" tall.
I have done three gear sceinerios with this truck.
I started with 3.73's in the stock dana 44 track lock.
Then Swaped in a 64' dana 60-2(5 lug dana 60) also track lock with 4.10's,
I Now just swapped in a 66' 9" with a pumkin from a mid 70's car with 3.00's & a factory ford track lock.
The 3.73's were good unless you went above 60 it started to feel like a waste of rpm on the highway. Difficult to pass above about 70, since it was hard to kick down above that.
The 4.10's were real fun around town, but sucked above 50! @ 75mph the
engine was turning close to 4000! Red line with the Isky installed straight up with a stock chain is 5000! A joke to pass anyone unless you were going slow.
The 3.00's are pleasant so far, However I have only logged a few miles on it.
I am having some early shift issues, where even in town it is shifting way too early under light throttle.
Also if I slow down, but not below 10-15mph, it doesn't kick back down into 1st on it's ownunless I mash the throttle, or manually shift it.
I am kind of worried about this since the cruise o matic doesn't use a vaccum modulator like a FMX does.
I will Say that even though the higher ratio kills a little torque, the torque multiplication from the converter lets it take off nicely! An added bonus of high gears with an automatic & stock converter.
I'll adjust the linkage to stock specs & see what happenes.
Y-ask Y?