i have been having some problems with my cat blowing when its hot. i took it off yesterday but couldent find any holes etc and it looked like it wasnt it that bad condition so i put it back on using some fire putty and it sounded alright but when it got hot it started blowing again and by then i had ran out of patience and day light.
One thing i did notice was that the springs that are used to keep tension against the manifold wernt under that much compression as the nut was hitting the shoulder on the bolt, how much should they be compressed? as i think it could be blowing from there.
Cheers all