390/330pi:
* It was a fair but unproven consensus on the FE Forums that most or all the 63 390/330PI had the c3ae-c "Denver" heads, so they had a CR of about 10.5 instead of the stock 9.6
* Not sure about 64. The stock CR went up to 10.0 so the "Denver" heads would have given 11.0 CR, almost 427 territory. NHRA Blueprint does list the c3ae-c heads as legal for both the 390/300 and 390/330 in 1964. But they list cc at 73.1 cc which would negate any added CR. In contrast, NHRA lists the 1963 390/300 and 390/330 at 64.55cc minimum so stock c3ae-c heads for higher CR are legal in 1963 but not 1964.
* Same intake
* Different carb but still a 1.12 Autolite 500cfm. Any "top shelf" 1.12 should do the job.
* My dad was on final line at Wayne and built big Fords/Mercs from 1952-1974 (after that they switched to the Maverick). He said about mid-year 1964 they ran out of the 406-style shorty iron exhaust and went to the flat logs instead. Not a good thing, so stay with the 406-style for sure.
* The cam, near as I can tell, is about 206-206 at .050 lobe. I've never had one to measure though. The early 1958 352/300 solid cam measures very close to that duration. So it's a little like an early 390GT cam at 206-206, but solid instead of hydraulic. I was going to use a Comp 264S IIRC to mock the 390PI cam. Seems Erson also had a decent clone. The Erson RV10M at 206-206 or Erson TQ20M at 216-216 would likely sound and perform like a 390PI cam. No noticeable idle at all, just clatter.
* Hopefully you can degree that stock 390PI cam as it is one of the remaining FE mysteries (the .050 duration).
* I grew up in the back seat of a P-code, and it was so much fun I bounced up & down in the seat as my dad wore the rear tires out, while I wore the seat stitching out. He didnt mind too much, within a year or 2 I was building Model A carburetors he got for $1 each.