No, second gear in the granny four speed is a little bit lower gear than first in the original three speed. It doesn't matter what the rear end ratio is. Every three speed transmission that I ever had, had a first gear that was too high in my opinion. I don't know what the ratios are but I think that third gear in the granny four speed is a little higher than second in a three speed. High gear is 1:1 in either transmission.
First in the 3-speed is 2.94.
Second in the 4-speed is 3.58.
It's a big difference and the main reason I switched from the 3spd to 4spd in my 216 powered truck with 3.55 rear end. It was a dog starting out, made worse by the 30-inch diameter 215-85-16 tires I had on it. Switched tires to something in the 28-inch range (like original 6.00x16 had) also made it better.
Can even tell a difference in the intermediate gear, which is 1.68 in the 3-spd and 1.71 in the 4-spd.
