I don't see doing this the hard way Charrlie. Judging from what the converter looks like, it's been used. How hard and for how long I don't want to even guess. However, again if it was me, while having the pilot changed, I'd get the converter shop to rebuild it, be it stock stall, or something perhaps a little higher, say something in the 2200/2400 range like the stock 340 converters. The engine also has been changed, and likely has more torque and HP than the 273 has, so wouldn't it may be a good time to have a look inside the converter and see what if anything is wrong inside and let the converter builder know that you've taken the 273 out and replaced it with a 340? I do agree that the later engine/transmission deal is the route to go, but like you say, if they wish to keep the shifter factory then the options for them are limited.