Sure - I'll take some measurements tomorrow. If I recall coorectly, I think I followed the TTI measurements for the later A-body big block cars (
http://www.ttiexhaust.com/MoparClassics-Headers/400IB-218/TTi400IB_Install.pdf). I'll double check tomorrow. I do know I mocked everything up and aligned the crank centerline/trans output shaft with the pinion yoke on the rearend before I locked everything down.
View attachment 1715448052
This may help too:
early a body big block engine mounts
I've heard angle milling some manifolds may work. I've also seen a couple guys swap sides and run manifolds out the front and under the k-member on the way back. A guy - Ron Thomas "Chassisman" over on Moparts has an early valiant with that configuration -
https://board.moparts.org/ubbthreads/ubbthreads.php/topics/1990015/1.html. I'll see if I can find photos.
Either way, it sounds like you're well on your way to the BB early A club. Can't wait to see the progress.