op amps in Ibanez SML mc1458

[e515062c]

I have one of these.  Sounds pretty good after cleaning up some hiss issues with a few well place caps and resistors.  Was trying different opamps in it as usual when I came upon these MC1448 in position 3 and 4 of the circuit.  How do they differ from the 4558 type opamps?  When I replaced them with 4558, or equivalent replacement I noticed significant decrease in output from pedal

http://www.us.oup.com/us/pdf/microcircuits/students/amps/mc1458TI.pdf         link to data sheet for  1458

http://www.freeinfosociety.com/electronics/schemview.php?id=588                   Link for ms10 as close as I can find to SML.

Thanks for any input

Carl