Yes, US Gen 2.5s with 3.5SOHC have 4.2X versus the 4.6X from original Gen IIs (oldest SRs with 4.88s aside).

Common swap is 3.5 sports that came with the 4.90s.

Also, in my past discussions with OldColt and the MT swap, he was advocating that swap first and see how the 4.2s with a 5-spd ran, then regear if still felt the need.

Big Truck: 00, 3.5, Endeavor, 5-Spd drive line in hand!
Little Truck: 87, 2.6T I/C, MT, LSDs, Tonneau Top
Her Truck: 03, 3.8, 20th Anniv, 65k
Daughter's: 06 Eclipse, Keeping it Mitsu!
FSMs: MitsubishiLinks.com