MikeD
Senior Retro Guru
Oh, and your cranks -- if they're both left-hand cranks then you have most of the unique bits of a tandem transmission. You'll need a normal drive-side crank for the rear right and a spiderless arm with a right-hand pedal thread for front right. With any luck your frame will have English-threaded bottom bracket shells, otherwise finding ISIS BBs could be a challenge 
