Can a new brand of power tube even duplicate what this pair of RCA's are putting out?

Having a difficult time finding a brand of tubes to match the wonderful low end tone this old pair of el 84's produce.   I actually pulled these old tubes out of a post ww2 era hammond organ, it was in my garage for 20 yrs.. I still cant get over the low end these old dusty RCA's are throwing out . I purchased two pairs of new tubes TAD EL84-STR  and The JJ's. Both didn't  even come close  

Was surprised about the TAD, they were suppose to have significant low freq. but compared to the RCA hey were a disappointment

 Any one have any insight on why this is, also any worthy brand suggestions to try?

Can’t speak to your specific tubes, but 1940s RCA tubes have outstanding low-end extension.
Google "Joe's Tube Lore" or call Andy at Vintage Tube Services. Cheers,
There are NO tubes being made that are as good as those RCA's which were sold in every drug and hardware in USA for two bucks. Nor will there ever be .
 Thank you very much sir , was  surprised  these old tubes had 50% more low-end I didn't know what was was happening. Now know to keep them in this amp..

You should try to pick up some 6BQ5/EL84 RCA's from the 1950s and 60s while they're still available. Usually, the tubes labeled for other companies or for organs (but are built by RCA) cost less than RCA logo.
And btw, blackplates have the superior sonics over greyplates. 
Yes check out brent jesse recording, 
Or Vintage tube services. They may have some WW2 tubes.
Or early 50s.