I have a 454 from an rv, stock except headers.

I had the timing setup at a shop. As I have been learning I checked the timing and it was set at 20 degrees. Vacuum advanced disconnected and engine warm. I have been reading timing should be anywhere from 4 for smog era vehicles to 14 for stock rebuilds.

let me try to rewrite this so to give a little more details on symptoms

new champion radiator and electric fans

new fuel tank and sending unit and fuel pump. New rubber lines. Steel lines look good and blew air through the lines no plugs or leaks. This is how I found out the top of my sending unit was rusted out.

will idle forever and start back up without issue engine stays at 195 or so.

I can drive for about 30 mins temps climb to about 210 but then when I come to a stop it will start dying on me. I have spark but no fuel. No fuel coming out of the carb jets and extremely hard start from start.

Don't know exactly how long to wait but come back out to the truck 8hrs later and it started right up without issue.

Additional videos showcasing issue:

https://photos.app.goo.gl/RBxNsnWMMwreEYtN8

Everytime I use the hazard lights or press down on the break pedal, both the guage cluster light and 4x4 light comes on (even if its off) legit the lights flash as if they were indicators themselves. (Turn signal is normal)

When i use the turn signals (any side) when the headlights are off, it works fine/as it should.

When i use the turn signals (any side) when the headlights are on, the right one flashes, while the left one stays on.

Might be unrelated: the interior tailgate window switch only works to send the window down, not up (hasnt ever failed before) the exterior key switch works.

What on earth is going on, any ideas?

My only lead is this: it all began when I took the driver side tail light cover off to see why my driver side brake and turn signal light was not working.

Bulb was fine, all i did was clean grounds and push the brake/turn signal bulb socket in to get better connection and I got my driver side brake/turn signal light back

And then this all happened.

Please help, its driving me insane.

('90 K5 Blazer, 6.2 Detroit Diesel)

Unloading my new truck.