440 cylinder heads

516 heads with what look like the small (1.60") exhaust valves. There's a lot of head material between the valve heads.

http://image.moparmusclemagazine.com/f/9535672/p39424_image_large.jpg

See, bugger all for material = large (1.74") exhaust valves.

Sorry to be a PITA but accuracy is important when it comes to BB heads as there are quite a few casting variations out there curtesy of Mother Mopar.