Do you need a different catalytic converter input/output diameter?
If you want a diameter larger than 63.5 mm then just cut the catalytic converter cone in the right one to the desired diameter and if 63.5 mm diameter is too large for the Shadow then you can get the reductions available in the link below:
Universal stainless steel catalytic converter with metal insert. Compatible with diesel engines.
The catalytic converter meets the requirements of the European directive:
Manufacturer's warranty: 12 months or 50,000 km.
KS21
Do you need a larger diameter than 63.5 mm? - Cut the cone in the right place. Want a smaller one? - use reduction:
MP501

MP20L

CP20A

CO19

CP20

MP22

KSS11
Do you need a larger diameter than 63.5 mm? - Cut the cone in the right place. Want a smaller one? - use reduction:
MP15

KSS21
Do you need a larger diameter than 63.5 mm? - Cut the cone in the right place. Want a smaller one? - use reduction:
MP50

DO-A19
Do you need a larger diameter than 63.5 mm? - Cut the cone in the right place. Want a smaller one? - use reduction:
DO-A21
Do you need a larger diameter than 63.5 mm? - Cut the cone in the right place. Want a smaller one? - use reduction:
.
DP-A25
Do you need a larger diameter than 63.5 mm? - Cut the cone in the right place. Want a smaller one? - use reduction:
MO20

MP-A50
Do you need a larger diameter than 63.5 mm? - Cut the cone in the right place. Want a smaller one? - use reduction: