Intermittents are a PITA.
Basics-all grounds
Engine ground to chassis.
ECU ground to chassis
Column ground, etc..
Points (condenser failing or shorting out) or electronic ignition (loose female barrel connector in plug)?
Ballast resistor continuity and connections.
Fusible link and bulkhead...
Just throwing this out there. I haven't tried it, but how about a couple shots of 3m 77 on the carpet backing and on the corresponding deadener area where needed? Weight it down over night.
Check all you can before you install.
What's up with the crank bushing or are you running a bearing? Might be a good idea to indicate the bell in if it hasn't been. The FSM has directions. Free downloads at MyMopar.com
Unfortunately, just because "it's new" doesn't mean no issues won't arise...
Do you know if the bell housing was indicated in with all attaching bolts torqued to spec?
I've heard some clutch covers can have conflicts with bell housings. One point is mentioned in the MP bible although it's a small block comment..........
Some bell housing info here may be...
I wouldn't think the Abody rods to be the same length as the Ebody due to the shift adapter bosses on the trans are further back.
However, there's this for the VGII....
https://www.shifterdoc.com/Hurst_3738180_Installation_Instuctions.PDF
1 (minimum) to 1-1/2 times the bolt diameter protrusion is typical.
Should not take that long.
What does your mechanical oil pressure gauge read with the prime?
FWIW, If you're going from the top with an assembly, pull the distributor.
Another option is to raise the rear of the car to cut some of the assembled angle.
On a big block, a deep oil pan may cause an assembly to be tight between the firewall and K-member.
I'm no body guy but I'll cite an observation from your OP picture.
Maybe it's a clue or no help at all but it appears your passenger side fender may be further forward than the driver side............
Same on '71 but omits "-3-2 bbl." wording.
If it helps, this is the 6 quart pan dimensions. Is this what you have?
If yes, IMO, just run 6-1/2 quarts, remark the stick and drive the wheels off it!:steering:
Some good reference in these for beginners....
https://www.forbbodiesonly.com/moparforum/threads/8th-edition-mopar-engines-book.309730/
Manual downloads here.......
https://mymopar.com/chrysler-master-tech-service-library-browse-model-year/