Tough maiden voyage - 1970 250 Automatic

[Number400]

Been working on this for a few months now and in the garage it starts right up, idles at 900rpm and drops to ~600 in gear. Carbs are set up as instructed in the Kopp manual and it has been a journey of learning.

So I get my wife and kids in for the maiden voyage and just as I backed out of the garage (from level to a hill), the car hiccuped but then came right back to a lumpy idle. Once on the street, it sputtered but got going then stalled at the first intersection a block away. After many many neutral drops, I got it around the block but could not climb the hill back to the garage. When put into gear, she sputters and the idle drops to ~100. If the ground was level, it can putt along at almost a stall sometimes. Back to square one as it runs about the same as when I got it.

Any ideas? Could it be the float height? Since it was fine on level ground?
The Haynes manual said 21-23mm WITHOUT the gasket and the Kopp manual said 21-23mm WITH the gasket. If the level is truly that critical, then I will put a thicker washer under the valve. Maybe I am barking up the wrong tree but my patience is wearing thin and I need to get it off the street ASAP.

As for troubleshooting, I felt I was close. My accelerator pumps are pumping, I can rev the car cleanly, it can hold any RPM, e-chokes are working, secondaries hold, everything has been checked and is set up as directed to the best of my abilities so far.

I will check vacuum again tomorrow, it was a stable 15 at last check. Too low?

Just needed to rant for a bit. Any experiences?

Thanks,
Edmund