i posted in the newbie area.I have purchased a 67 camaro that has a 3 speed column shift.I want to convert it to a 4 speed floor shifter car.The car has a 10 bolt with a 3.55 posi with a 245/45 r17 tires with a 350 sbc motor.I wanted direction with what gear ratio in a 4 speed transmission would make the car fun to drive.i one day want to go to a 383 stroker.
one last question will it have to have a new drive shaft from the three speed to 4 speed?

 

I would suggest one with 2.52:1 first gear ratio, commonly called 'close ratio' Muncie.
The following require no driveshaft changes: 3- & 4-spd manual (Saginaw & Muncie), and THM350 automatic (3-spd).
The following require driveshaft rework: THM400 (3-spd), THM700R-4 (4L60 & 4L60E).

 

Change 2.52:1 to 2.20:1 - my EDIT button does not work correctly.

 

Read more here :
https://www.gearvendors.com/cg2wdt.html

 

Close ratio Muncie for sure but I'd be thinking about finding a 12 bolt rear,the fun stops when that 10 bolt posi breaks, especially if it takes the driveline and trans tailshaft with it.
Stay away from the Sagainaw 4 speed if you plan on a 383 with some power. Better to build a stout drivetrain first and add power later than do it all twice when you break everything with a strong motor.

 

The regular 4-speed M-20 is called a wide ratio and has ratios of 2.52:1, 1.88:1, 1.47:1 and 1:1. The M-21 and M-22 are called close ratio and have ratios of 2.2:1, 1.64:1, 1.27:1, and 1:1. The M22 is called a stone crusher because of the straighter cut of the gears.
Many people prefer the M20 for street driving because of its 2.52 first gear. Road racers prefer the M21 because the close ratios keep the rpms up while racing. People prefer the M22 because it stronger.