I recall seeing numbers posted from Car Craft putting them roughly in order from least to most HP loss: PowerGlide 200-4r T350 700r4 T400 4L80 but don't quote me on this. I figure if I want an auto I'm going to have to sacrifice power.
'53 BelAir 261 3spd/OD 4dr '54 3100 235 3spd '79 C30 with a '51 235-'57Bellhousing-'67SM420-14bolt dually '89 V3500 350/465/205 SRW CC One Chevy just isn't enough.