Olds did not use multi carbs until the J-2 in '57. '49-'56 will not interchange, so your only choice is the aftermarket. One company is still making them.
The
'53 '49-'53 "dual quad" will bolt on, and will work OK. The
'54-'56 "triple deuce" will be a better match, to your '54 heads.
Linkage is easy to fabricate, but finding carbs, to fit them, is a separate problem.
Used ones turn up,
on eBay, and
the H. A. M. B. from time to time.
Norm