BN-621A/BN-621B/BN-621C/BN-621D/BN-621E/BN-621F/BN-621G/BN-621H
| Part Number | Sensor | OEM Number | Gasket | Additional Info |
| BN-621A | sensor in front of body | 165131701C | donut gasket | 3 bolt inlet, 2" rear pipe, 18" around body |
| BN-621B | sensor in front of body | 165131701 | donut gasket | 3 bolt inlet, 2 1/4" rear pipe, 18" around body |
| BN-621C | w/out sensor | donut gasket | 3 bolt inlet, 18" around body | |
| BN-621D | sensor in front of body | 535131701 | donut gasket | 3 bolt inlet, 20" around body |
| BN-621E | sensor on outlet of body | flat gasket | 3 bolt inlet, 20" around body | |
| BN-621F | sensor in front of body | 535131701R, 353131701B | flat gasket | 3 bolt inlet, 20" around body |
| BN-621G | w/out sensor | 028131701B | donut gasket | 3 bolt inlet, 16" around |
| BN-621H | with sensor | 13571, 1HM131, 701HAFT | donut gasket | 3 bolt inlet, 8" rear pipe, 11" body length |
Specify the following: OEM# required; number of bolts in flange; center bolt measurement if a 3 bolt flange; number of sensors; location of sensors; flat or ring gasket; rear pipe size; size around converter body (not length)