904 vs 727

71 Demon in resto.
I have a 81 904 that is rebuilt, (last time it was out about 5000mi) I am installing a 360 with a 272 cam but cannot find a 2400 stall converter for this lock-up trans. This is not going to be a race car.
I have a 727 sitting on the shop floor and could rebuild it to replace the 904, converters are available from several sources for this trans, plus beefier. I'm already swapping out the puny 7 1/4 for an 8 3/4 so the driveshaft will already require shortning and balancing.
What other snafus could I run into; linkage, coolant line fitment etc.
Thanks in advance for the assistance.