In the past, I've run a SM465 with no gear reduction box and felt in some cases, being lower than 60 to 1 was in order even with a SBC. For the record, this will be a 5.0L SBC to SM465 to GRB to an offset tcase(LC, Dana18, etc)

I've got a few different choices as far as gear reduction boxes go:
- NP203
- NP203 w/ 3.6 conversion
- Klune
-custom build a box

With the NP203, I've got to either get a SM465 version(bit of a bitch... but I've had/sold two of them:p) or make an adapter (cost about $500 or so in addition to mating it to the tcase) The adapter to the tcase will cost me about $300(I've got half of it:p) So, to do this option, I'm looking at approximately $800-$1000.

If I go with the NP203 with the 3.6 to 1 conversion, I'm looking at an additional $1000.

I'm not really considering the Klune due to limited "small" adapters for their box but mention it in passing.

The other option I have it to custom make a gear reduction box. Going this route, I think I can make a box that will be as bullet proof as the NP203 gear reduction box but take up two inches less of my drivetrain space. The actual box would be about 6 inches long. The "adapter" to the SM465 would be about 2 inches long. And there would be no needed adapter to the tcase I choose. The downside of this is the amount of machine work I'm looking at. I would need three gears/shafts modified(approximately $800... probably less) Plus, I'd need a bunch of machine work for front and rear case mods(approximately $1000 for complete case and mods needed) Thus I'd spend about $1800-$2000. But, the low range I get out of this gear reduction box would be insane depending upon the gears :p

Given this information, which route would you look at?