You'll also never get oil pressure from one of those pumps by cranking with the coil lead off, the nature of those external oil pumps is they need to be spinning at operating speed to work, cranking won't build pressure in them.
These engines can be hard to get initial pressure.
I always pack the oil pump with vaseline/petroleum jelly (and I mean pack it, completely, no gaps, no air pockets) and have always had oil pressure on first start. I've not ever tried to pre-fill them manually with oil. Petroleum jelly is how most have done these for decades and is the most effective method.
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Is the cam gear meshed with the oil pump correctly and the oil pump drive rod connected to the pump correctly? maybe the pumps just not spinning.
Either way, if this is the first start of the engine be very careful as you've now wiped all the break in lube off the cam lobes be cranking it with the lead off for a while trying to get oil pressure. The flat tappet cams need to be started pretty much instantly and brought up to 2000rpm for 20 minutes to break in.
Excessive cranking or letting it idle etc without breaking it in will end in tears. If it were me I'd be pulling the cam and relubing but thats just me. I've seen what can happen to fresh engines when people can't get them started.