340 Help
You don't need to change the front drum, you need the correct reaction shaft for the non lock up trans along with the input shaft and valve body. There are different front drums but it gets a little confusing as to what fits what.
Basically there are 4 disc front drums with non lock up R/A shafts. Then there are 5 disc front drums for non L/U and L/U transmissions. The drum is the same but the reaction shaft is different. You can modify a L/U R/A shaft to make it a non L/U shaft by removing one ball plug. Compare to a non L/U shaft to see which one needs to be removed.
There are also differences in the rear clutch drum interface with the R/A shaft so be careful if you are mixing and matching parts.