A833 gear interchangeable?

I have 3.23 rear gears in my 65 Barracuda. With the 3.09 low gear I had originally and now have in the later case, the overall low gear ratio is 9.98 to one (3.23 x 3.09). When I first put the later trans in back in the seventies (the original mainshaft had a groove worn in it and at the time I could not find a replacement early style mainshaft) my overall low gear ratio with its 2.66 low gear and 3.23 rear gears was 8.59 to one. That low gear ratio was essentially equivalent to running 2.76 gears behind a 3.09 low gear. HUGE difference off the line. Turned a good running 340 into a dog. Had to put up with that for a couple of years, until I learned the original gears would fit in the later case. Fortunately, I had saved the original gearset.

By the way, with a 2.47 low gear and 3.73 rear gears, the overall low gear ratio is 9.21 - taller than the overall low gear ratio with 3.23 gears and a 3.09 low gear.

I never had a problem with the rpm drop from first to second. Just wind it a little tighter in low. I run it out to 6500 in low gear, 6,000 in the top three gears.

The worst transmission gear set for any kind of street gears was the old GM close ratio 4-speed with its 2.20 low gear. To get an overall low gear ratio equivalent to my 65 Barracuda with the GM low gear, you'll need 4.56 rear gears.

Back in the (recent for me) day, those 5 liter Mustangs were quick off the line because they had something like a 3.35 low gear. Gave them an overall low gear ratio of better than 9 to one even with 2.73 rear gears.