23 spline to 18 spline

The only thing interchangable between an 18 spline and 23 is the main out put shaft. This is were most of the 18 spline A body trans came from, somebody took a B body trans and put an A body main shaft and tail housing on it. There are 2 gear sets for the 18 spline(2.65wide and 2.44close ratio) and 3 for the 23 spline(3.09, 2.66wide, 247 close) excluding the OD trans. plus a few race gear sets that where sold over the counter. YOU CAN'T MIX gear sets, not between 18 and 23, 18 to18 or 23to23, the whole gearset most be changed. All 18's are coarse pitch gears and the 23's are fine pitch gears, There are different input, cluster, and main shaft gear between each gear set.