A: The only thing is the flexplate needs to be balanced to the motor or vice versa (otherwise it'll vibrate) Some of the 304/360 swaps have had bad vibes and some you can't even feel the difference, but 401 is a LOT different. Speaking of 998s, I have one from an Eagle (converter was locking up too soon) for core $25, and a 727 from a Jeep that I am going to swap in a 2WD outputshaft from the Mopar trans I have (my son is putting it in his '83 Cherokee offroad buggy with a Mopar 360) $25 takes those parts too. (In Seattle) From: farna@xxxxxxx Subject: Re: 401 flexplate..question To: mail@xxxxxxxxxxxx Message-ID: <ADVANCES6286hBzfRSb0000395a@xxxxxxxxxxxxxxxxxxxxxxx> Thanks for verifying, I thought the flexplate was useable for all Chrysler auto trannys. The 998 is substantially stronger than a 904 though. On July 14, 2005 Bill Dettman wrote: I've been running a 998 behind a 401 for almost 10 years in my Javelin. The 998 originally was behind a 304. I run 13.16 or so with it. The flexplate worked just fine. There are two sets of holes. The 904/998 uses the inner ones, the 727 the outer ones.