One thing is for sure. You won't need a loose converter for that 540. Something very similar to a stock hemi/383/340 torque converter, but built to take the torque, will flash well over 3000 and drive like a stocker, making it a very fun, responsive hotrod!
I used a stock hemi converter(while it lasted!) behind a 535 with ported 906 heads back in 1981. If i recall correctly, it stalled about 3400 or more.