ok,I have a 94 400l 4x4 and as you know it is a 2 stroke,If I come across a 96 magnum 425 engine can I fit
it in my 400 frame without much modification besides the fact of the engine mounts or are they the same too?
Anyone done this?

 

Why on earth would you want to do that? The 400 2stroke will DESTROY the 425 4stroke......

IMHO: you are FAR better off putting the money into the engine that is already in the machine.

 

I SUNK $600 INTO MY 350 ENGINE,IF MY 400 GOES OUT I WILL JUST PUT MY 350
ENGINE IN IT BUT I AM NOT AFTER SPEED BECAUSE THATS WHAT THE 350 2X4 IS FOR RIGHT
NOW,IF I CAME ACROSS A 4 STROKE I WOULD WANT TO PUT IT IN MY 400 4X4 BECAUSE
ITS JUST FOR MUDDIN,TOWING,AND WORKING AND A 4 STROKE WILL LAST LONGER EVEN THOUGH IT PROBABLY WOULD NEED REBUILT,RIGHT NOW MY 400 HAS 40000+ MILES AND I
BELIEVE ITS ON A ORIGINAL PISTON,NOT MUCH LONGER FOR IT PROBABLY.AND I MIGHT BE ABLE TO GET A 425 4 STROKE CHEAP SO THATS EASIER THAN REBUILDING A OLD 2 STROKE
WHICH WILL PROBABLY HAVE A OIL AND WATER PUMP GO OUT SOON........