Some noob questions

[kennyele11]

Got the timing sorted out thanks to Tom, just had to switch the two wires in the black box on the side of the distributor and nI was able to set the timing to 0 degrees. Now a new problem persists. Immediately after starting the engine a persistent clicking noise happens. It sounds like it is coming from underneath the valve cover. Could this be due to the valves not being adjusted properly? Also I regrettably rotated the engine backwards during this whole timing process not knowing I wasn’t supposed to do that. Although I rarely rotated the engine backwards - at most maybe a quarter turn.

[notoptoy]

Certainly take the time to set the valves, then you know for sure and can rule it out. Glad you got it sorted.
EDIT: I just got your e-mail, set the timing to 16 degrees before TDC for an R16, or 20 degrees before for a U20!

[Gregs672000]

You're not going to hurt anything turning the engine backwards.

If you have replaced the distributor then I would assume it now has the non-smog ignition curve in it, so timing should be set at 17 degrees at 850-900 rpm with no vacuum advance line hooked up. Set it with the timing light and adjust idle speed at the carb linkage as needed to maintain idle rpm.

Adjust the valves cold to 6 intake 8 exhaust. A U20 tends to make a fair amount of clatter. Some are more quiet than others. They make a different and louder clatter when they are not yet getting oil to the top, and if that sound lasts very long then we need to check some things like oil pressure.