1969 Valiant Diary
Hey Swifster, here's a pic of the finished 1968 Valiant "400" our Inland Mopars Car Club built as our charity benefit project car some years ago. It started as an Arizona car that was pretty rough when purchased but was able to be driven back to SoCal.
We called the finished car a "Valiant 400" because we stuffed a 400-cid big block/727/8.75 drivetrain under it. We also put a complete RMS Alterkation/StreetLynx suspension under it. It was both a sweet driver and great handling setup.
You said you're unsure of the drivetrain right now. If it was me, I'd go with a 360/200-4R overdrive combo. This is what I'm putting in my '69 Dart. The 200-4R fits in the unmodified A-body tunnel and has a 0.67 OD.
Good luck with your build and please post progression pics.