I'd say it's best to measure everything before you start cutting.
Technically the front of the new cat should slide over the existing "y" pipe(s) so they flow into the cat. Likewise with the rear. It should go into the existing tail/intermediate pipe.
If you can get an accurate measurement and it's close you may be able to rent a tailpipe expander from an auto-part store.
If not, you can purchase sleeves and clamps the sleeves are 2/3 dollars each and the clamps are about a dollar.
On a different note. If your cat is clogged and not hollow check a couple local scrap yards because it's a large domestic and worth anywhere from 75-125 dollars scrap.
Technically the front of the new cat should slide over the existing "y" pipe(s) so they flow into the cat. Likewise with the rear. It should go into the existing tail/intermediate pipe.
If you can get an accurate measurement and it's close you may be able to rent a tailpipe expander from an auto-part store.
If not, you can purchase sleeves and clamps the sleeves are 2/3 dollars each and the clamps are about a dollar.
On a different note. If your cat is clogged and not hollow check a couple local scrap yards because it's a large domestic and worth anywhere from 75-125 dollars scrap.
