A Weiand cross ram 6 pack with carbs would be worth 2500+ if it is like new condition , I am not sure the intake is available anymore & it could be worth 500 or a lot more if it isn't , the carbs are 600 each + linkage fuel lines Air cleaner etc
IS it worth installing is a big question , the stock 6 pack can be beaten easily in HP by a Holley Street Dom or the eddy RPM & a big 850-950 Proform carb , but if you want looks the 6 pack rules !!
Power wise I am not sure , the Weiand 6 pack is a whole different animal & with the race carbs [accelerator pumps on all the carbs ] & a better intake you should be able to make a lot of power & the single 4 bbl may not make more power , I believe hood clearance will be an issue though .