Put the 65's back in, its not a jet problem. Its an enrichment problem. Your 31 squirter is probably fine, odds are you have a power valve that is opening too late, but if its new out of the box I doubt that too. You rarely if ever have to rejet significantly. You probably have a 6.5 PV, if you have less than that, buy an 8.5 for a mild motor. In the very least put it back to stock. The biggest relationship to jet size is carb venturi size, so rarely do you go more than 1-2 either way anyway (unless you get rid of a power valve which is a different story)
Here is the next thing, make sure the float level is no-kidding just dribbling out of the holes. 1/8-1/4 inch too low will cause a lean condition on some motors
Then turn your idle mixture screws in one at a time, it should start to stall, then back them out until it idles the fastest. Lower the idle speed on the linkage back to where you want it, then repeat the idle mixture adjustment. If it DOESNT kill the motor when you turn the mixture screws in, you have a vacuum leak somewhere, probably your intake.
Bottom line, if you are 100% positively sure you dont have a vacuum leak. Its either a PV with a value too low, a squirter problem, or a float level problem. I am sure it isnt a squirter, it probably isnt the PV (unless you have a completely stock cam or close to it) and the float level is easy to misdiagnose, you want it to just dribble, not "just dribble when I lean on the fender" because we all lean differently LOL
Let me know what you come up with.
70 Sportsroof, 427 FE, 489 cid, 10.7:1, Erson valvetrain, KC ported Edelbrock heads, modified Massflo EFI, TKO-600, 31 spline 4.10, A/C.
71 F100 4x4 shortbed 445 FE, ported iron heads, ported RPM intake, Bullet custom solids, 1000 Holley
13 Ram 2500 Laramie Quad Cab 6.7 diesel