The 1.76 gear is alot bigger. Lets see, on the 1.76 gear the gears you see will come to the edge of the base on the plantetary and the 1.82 will be about an inch from the edge.
Instead of upgrading your stock powerglide you might try buying a used powerglide thats already setup. You should be able to get one, not tricked out, but that would work in your 402, from $700 to $1000 ready to go.