i run jb conversions original kit with a speed sensor out of a jeep dana 300. it will only work if you have a mech driven speedometer. if you have a factory electonic speedometer (89 and newer s series) painless wiring an electronic pickup thing that goes inline with mech speedometer cable and sends an electronic signal for the speed sensor. they offer 2, one for tbi one for tpi. It is designed for fuel injection engines with older trans/tranfer cases.
http://www.jegs.com/webapp/wcs/stores/servlet/category_10001_10002_15503_-1_10409
look at the bottom of the page
i think when i ordered my jb conversions kit over 3 years ago they said the kit for the np241 would work for chevy 231 and use the stock speedo, but that was a while ago, you'd have to call and ask
http://www.jegs.com/webapp/wcs/stores/servlet/category_10001_10002_15503_-1_10409
look at the bottom of the page
i think when i ordered my jb conversions kit over 3 years ago they said the kit for the np241 would work for chevy 231 and use the stock speedo, but that was a while ago, you'd have to call and ask
