Hi, Greg -
No question the J's 70" drivers would give more tractive effort than the later Daylights' 80" wheels,
but the GS-2's had 72" drivers and could probably pull more - but not as fast - as the GS-4's and -5's.
Also, the Daylights all had boosters on their trailing trucks, and so could start a pretty heavy train.
Did the J's have boosters?
Only two of the Daylights -#4458 and #4459 - had roller bearings on all axles, and not even those two had roller bearing rods. IIRC, the J's were designed a few years after the Daylights, which were basically a 1936 design with a few later upgrades, and the J's had a higher boiler pressure. They were both fantastic locomotives. It's a shame that NS killed their steam program, so we'll never see a J and a Daylight running side-by-side.
- Russo