E-V T35 :
The earlier T35 version came with an ALNICO magnet, 16ohm impedance and 57dB EIA sensitivity rating.
Later (end of 60's) was introduced the T35A with 8ohm impedance and still 57dB EIA sensitivity.
In the beginning of 70's, E-V documents change EIA sensitivity to standardized sensitivity and so rated T35A with 104dB @ 1W @ 1m .
2 versions : ALNICO round magnet and later CERAMIC rectangular magnet (1978) with same given characteristics.
This is valid of course for recent speakers. Due to ageing of alnico magnets, the sensitivity of your T35s should be slightly less now, if older than let's say 10 years.
Best regards,
ERIC