Retrofit 78,79 cis to later SC's

Does anyone have any experience retrofitting the cis from a 78 or 79 SC to later SC's?
The intake box and runners are larger on the earlier cars at 43mm vs. 39mm for 80 thru 83.
The 43mm system was also used on euro models all years. The HP rating for the 78,79's is identical to 80+ despite a lower compression ratio of 8.5-1 vs 9.3-1. There would seem to be a possible power gain available by backdating to the larger intake cis