LA small block timing is suddenly way off

Thanks for the help, guys. I found the problem to be a leaking float in one of my Edelbrock carbs. Sorry for the wild goose chase on thinking my timing was retarded, I guess it was me that was mentally challenged. Found a float kit nearby and had it running shortly after. With timing light I set timing to 10° advanced at idle, which was about 30° advanced at 3,000 rpms. I could easily tweak this if needed.

Before finding the carb problem I followed the earlier recommendations. Piston stop tool, confirmed the reference mark on harmonic balancer is correct for cyl 1 TDC. Checked timing chain slack to be about 6° crankshaft rotation by observing distributor rotor and turning motor by hand. Verified cam phasing by watching rocker arms for cyl 1 at TDC exhaust stroke. Tested my MSD ignition box ability to spark, per MSD test instructions.