I ordered a long skinny flex magnet will be here Tommorrow., and I’ll look for an access plate when I craw back in there 

Do you see any access plate or inspection plate or dust cover plate at the bottom of the bell housing similar to what I marked in the photo?

with the oil pan on, look between the oil pan and the bell housing 

It a top mount starter , LS3 motor

I’m not sure about your engine configuration, but maybe you could find it by fishing around with a magnet on a pole thru the hole where the starter was located (bottom mount starter?) or maybe you can find a plate on the back of the bell housing at the bottom that you can remove and fish around.

Sounds like we have a similar problem. Mine is an '01 with a Holley (not sure which one...4150?). I had mine rebuilt last year and initially ran well but by the end of the summer, was having some stalling issues (vapor lock??) and lower than normal idle (500-ish). The good news is, while doing yearly maintenance in the driveway, it fired right up and held it the idle, albeit lower than prescribed. I believe cap, rotor, wires were all done back in 2017 so that may be an issue. My knowledge only goes so deep. What I've learned on this forum is it literally could be 25 different things. Anyways, I'm going to bite the bullet and take it to Malibu tomorrow. Hopefully they still have a few techs on hand familiar with the old school stuff. I know they sent the carb rebuild to a third party local guy. Head tech said my boat is literally the only carb engine they service these days.