according to Joe G:

http://www.quickperformance.com/SuspensionInfo.html
The monte carlo (uses metric studs (82 & up)) is 58'' wide. what you have now is 60''. I think you should talk to someone who has one to be sure but I don't think so. You only want to do this once, so be sure. measure and measure again.

In general ....... depending on the your rim width and the brake drum relationship, how it sits, brake shoe size, and using narrow vs. wide (modern) rims all ties in w/ engine size and torque specs.
For gearing see: smokemup
http://www.smokemup.com/auto_math/index.php

for gear ratios involving the tire size, tranny, rear end gearing ... it tells you the speed at what X?X?X? ratio you plug in and RPM. You calculate what is best for your situation.
yes to the engine and tranny.

Gooday
Jim

small wheel moves by fire and rod,
big wheel fires by the grace of god,
everytime that wheel turns round,
bound to cover just a little more ground.