Actually, B-47's could carry conventional bombs and were wired for that, but as this was the period when the USAF wanted to get rid of all conventional ordnance, so training was lacking and they were rarely carried. Also, the conventional load was nothing to write home about in the later versions (B-47E-IV and onwards) with the short bomb bay (though the short bay and long bay were interchangeable in maintenance, but only on "certain aircraft" and only up to B-47E-III).
The "high density" conventional kit (long or short bay) could be fitted to airframes from #617 onwards (only 500 kits were ever produced), "low density" conventional kit (short bay) only to airframes #617 through #730. High Noon and Ebb Tide progarms modified B-47B's up to E standard so presumably they could fit the "high density" kit only after those modifications.
Loadouts were for B-47B:
Long bay, low density kit:
2 x 4000lb or 9 x 2000lb or 16 x 1000lb or 16 x 500lb WW2 box fin bombs
6 x 2000lb or 8 x 1000lb or 8 x 500lb "interim design" bombs (WW2 fitted with new conical fin)
1 x 25000 lb
8 x 750lb (M117)
Long bay, high density kit:
6 x 2000lb or 18 x 1000lb or 28 x 500lb "interim design" bombs (WW2 fitted with new conical fin)
1 x 25000 lb or 1 x 12000lb or 1 x 10000 lb (I assume these are nukes though, or did the US have Grand Slams and Tallboys?)
4 x 3000lb (M118) or 21 x 750lb (M117)
Short bay, high density kit:
3 x 2000lb or 6 x 1000lb or 13 x 500lb "interim design" bombs (WW2 fitted with new conical fin)
7 x 750lb (M117)
For B-47E:
Long bay, high density kit (only on Block III and prior, strangely low density kit is not given as an option here):
6 x 2000lb or 18 x 1000lb or 28 x 500lb "interim design" bombs (WW2 fitted with new conical fin)
1 x 12000lb or 1 x 10000 lb
4 x 3000lb (M118) or 21 x 750lb (M117)
Short bay, high density kit:
3 x 2000lb or 6 x 1000lb or 13 x 500lb "interim design" bombs (WW2 fitted with new conical fin)
7 x 750lb (M117) or 6 x 750lb (MC-1 chemical cluster)
Short bay, low density kit:
3 x 2000lb or 4 x 1000lb or 8 x 500lb "interim design" bombs (WW2 fitted with new conical fin)
4 x 750lb (M117) or 4 x 750lb (MC-1 chemical cluster)
Source: Detail & Scale #18