All Right. I tried my best on my own before asking for help. Got the thing almost right, but still have a couple of nagging symptoms.

Engine:

1969 144s, B20b with different head than original, dual SU HF6's (not Strombergs as originial), with ATF and KN needles. Secondary throttle removed/blanked. 10 degrees advanced (I think*). Crane X700 ignition properly set, new cap, rotor, wires and plugs. Distributor has vacuum diaphram - not hoooked up -- and there is no nipple on the intake. Brake booster check valve is rattling. Possibly some shaft leakage on the SU's.

Using several SU specific tuning instructions, I manage to balance the airflow (Uni-Syn), set the mix (15 flats front carb, 17 flats rear), throttle stops backed almost off to yield 950 RPM hot idle with minor fluctuation. Engine not overheating, nor pinging. Choke and fast idle set as per Haynes procedure.

It just keeps stalling when I come to a stop.

And the engine "bucks" anoyingly when up-shifting. Possibly when cruising, too, but it's hard to tell.

*Engine timing verified, but I can't read my crank pulley timing marks clearly enough to say what I am using. What do these say? (10-0-10-20-30-40, I think?)

After a hard run, at a stop, I need to keep my foot into the pedal in order to keep the engine running. After a bit of siting there, the idle will eventually take up its 950 RPM's (no tach, just sounding this).

It is also hard to start:

Cold: Jumps to life with full choke, only to sputter and slow toward stall within 30 seconds. de-choking to about half helps.

Hot: Need to keep my foot into the throttle to get/keep it started. Can push back the choke to none within normal drive time. Can keep engine going with some choke after hard run to prevent stalling.

So, what is going on?