Can I GET A JDM B20 A CARBED ENGINE AND JUST SWAP OVER THE HEAD AND INTAKE? As long as the lower end is the same then that's good enough I hope.

Everything will bolt right up if that's what you're asking. You'll also need the fuel injected exhaust manifold. From everything I've read, the bottom end on the JDM b20a carb'd engine is the same as the fuel injected engine. I do know that the carb'd b20a3 has thinner piston rods and rod bearings, but I have never seen anything documenting that's the case with the JDM version. I say try it and see. Even if there is a difference I don't see it causing any issues with a stock fuel injection system. The difference in power isn't significant enough to cause any issues, but you'd want to keep in mind the carb'd engine redlines at a lower rpm than the fuel injected ones. Please post back if you do this, and let us know if there is a difference or not.

__________________
1991 Prelude Si ALB 4WS
2017 Ram Rebel

The JDM B20A is a very tough thing to find.10 YEARS AGO IT WAS NO PROBLEM.

That's true. I've bought two b20a's in the past, but the last one was in 2010. I haven't seen one around here for several years, but I have seen them listed on ebay from time to time. Are you looking at buying this engine from ebay?
https://www.ebay.com/itm/Honda-Prelu...33K:rk:49:pf:0

__________________
1991 Prelude Si ALB 4WS
2017 Ram Rebel