I just got off the phone with Bullet racing and they don’t have any Mopar flat tappet cores. Does anyone have them? I have not checked Comp because of all the problems. Anyone have any knowledge here? I’m not really wanting to go with a roller because of the noise but I’ve heard that some are having better luck with a small street roller and a solid roller lifter set at .006 lash A friend is going to dyno a roller 440 with Isky hyd rollers that are supposed to be quieter.

I ran Comp custom ground solid roller in my last stroker BB pump gas Duster that was 260@.050 on the intakes with .420 lobe lift,266@ .050 with .409 lobe lift on the exhaust lobes ground on 108 LSA.I would set the lash at .012 to .016 hot and it was very quiet when warmed up, sounded like a medium to big flat tappet hydraulic lifter street camshaft
If I was you I would buy a hydraulic roller camshaft and run, use, a set good quality solid roller lifter on it with .002 to .005 clearance when hot and enjoy

I was told the same thing so I told them to make it out of steel instead. They had done this for me before. This, along with tool steel lifters, should eliminate to "junk cam" problems. But of course it ain't cheap, I think the cam and lifters were about $1,350. And you run a bronze distributor gear with these.

Try one of the smaller cam companies like Schneider, Jones Cams, or CamCraft?

Most flat tappet cores come from CMC in Michigan as identified by 'CMC" cast into them between the lobes. It's where most domestic cam places get their blanks to start with.

I don't know if CMC sells individual cam cores to Joe Public, but if they don't maybe they can guide you to where to find their stuff. https://camshaftmachine.com/

Could try Racer Brown as well. I had issues finding a Small Block solid flat tappet cam due to the larger companies not having cores. He at the time has a good stock of atleast small block cam cores.

You might also consider an Oregon Cams new camshaft or send in one of your used (but known good) camshafts for a re-grind.