340 six pak setup

Picked up a edelbrock 3x2 set up at Carlisle past Sunday
Question. 70 FSM has zero info on 340 6 pak I know the text info for the 440 6 pak is a good guide and probably identical to the 340
But where can I get the specifications Holley 2 bbl carbs
Front / rear. R4789. R4790
Also the center carb is a R4782
Date code 2460. =. 9/3/70
So it's a 71 carb
But not listed in FSM. or The white guide books by Galen G
Any info appreciated
Thanks