When I got the car the only thing left of the speedometer cable was what was hanging from the transmission. I have a brand new cable ready to go in but where is the proper location for the the cable to penetrate the firwall and I guess I'm probably missing a gasket or something to protect/seal?

And the year is?? There are differences.

Here is the location on the firewall for a 66 or 67 at least.

See Dale is ready because he has all his holes circled:D

When you get old and start losing eyesight, you circle just about everything. :thumbsup:

More specifically, that location is for the Muncie 4-spd application only as all other transmissions (3-spd, Powerglide, and Saginaw 4-spd) used the hole under the steering column. The hole under the steering column gets a plastic plug when a Muncie is used. Also notice the cable retainer below the hole; there is a second cable retainer welded to the under side of the floor pan.

There should be a grommet at that hole.
Bruce

NPD has replacement grommets.

More specifically, that location is for the Muncie 4-spd application only as all other transmissions (3-spd, Powerglide, and Saginaw 4-spd) used the hole under the steering column. The hole under the steering column gets a plastic plug when a Muncie is used. Also notice the cable retainer below the hole; there is a second cable retainer welded to the under side of the floor pan.

There should be a grommet at that hole.
BruceBruce is correct this is the hole for a 4-speed. The poster mentioned in other threads he had a manual trans and I kinda concluded he meant a 4-speed. Shouldn't have assumed that and posted with the caveat. :)