is there any benefits to installing 1.4 rockers on a stock 1600 with dual carbs?

Your going to bind those stock springs and i don't think the stock vales are going to be long enough for the added lift. On a stocker just keep it simple and reliable. Build a mild 1776 if you want a little extra umpf, or even better yet put fuel injection on that stocker

yeah, it works fine and will give you a bit more power when paired with dual carbs and a decent exhaust. It gives you about 27% more lift after all at the valve but the duration remains more or less unchanged. I think aircooled.net even sells a kit to do it that comes with the proper length pushrods for a stock 1600.

I put 1.25's and 34 ict's on my 1600 single port and it's like a 2332cc street screamer now.
I highly recommend it.