[nvrdone]

I've got an axle from Sid's and its great !. Sid is a big help with any questions you have.
One thing you have to watch for is scrub line. That's the line between the bottom of your rims and the bottom of the axle. Imagine your rims with no tires mounted on the axle. You need clearance so that if both tires were to come off the rims while driving ( has that ever happened ? ) the axle wont drag on the pavement. On my '49 I went with a 3" drop and 15" wheels which gives me about 1/2" clearance.
You also have to have a new tie rod with new ends so you can mount it under the tie rod ends for spring clearance. Then get your caster right and it will drive great.
I can cruse at 70 + and the truck tracks straight and steers easy.
If you want really low and a new car ride go independent. If you want the trad look and a good ride go dropped axle from Sid's