Mechanical fuel pump

I thought so. LOL
I can't find a 12-383 on their website. Looking in their 2014 catalog now.
There's an 12-838. It's not particular good by the specs. Reminds me of their Chrome fuel pump which also had a high cutoff pressure and unimpressive capacity.
The 110 pump (p/n 12-360) has lower cutoff pressure - or at least used to. I never put it past any company to change something but not change the public part number. Grrrr.

Yes. Stock pump should be fine. Hopefully you won't need to put a regulator on it. Make sure you mount the filter with the outlet higher than the inlet when you change the carb line for the 4 bbl. That will help.