2 piece driveline upgrade options

[cortcomp]

Sorry if this has been covered, i didn't see anything searching that answered:

I have the small, 2 piece drive shaft. The mount for the carrier bearing is the kind where the bolts are in-line with the driveshaft. I am swapping in an NP440 trans which is pretty close as i recall to the 3 speed, so i may not need a new driveshaft. However, if it's too long or short, i've read the smaller driveshafts aren't that desirable. Add in that i have OD and 3.73 gears, and that tiny shaft will be spinning away.

I know a larger diameter shaft resists failure from the "jump rope" effect, and i do have a 327 albeit it's stock rebuilt and won't be a performance truck, so i'm wondering if i shouldn't just go to a larger all new driveshaft and be done. However, i see the larger diameter carrier bearings mount with bolts side to side, not front to back, and i'd have to check again but don't think my chassis would accept that...

So what do you guys do? It's a LWB and with OD i think 2 piece is still safest here, and i don't mind buying a new shaft balanced and new joints, etc, but not sure what sizes i can go to because of the bearing. It's the standard 1" drop in front and 3" drop in rear with CPP springs, everything else stock suspension.