So very stuck...

So I have hit a wall, not literally. Under light throttle my truck runs fine, shifts through all its gears no problem. I step on the gas and I get this horrible rattling sound. Like the motor is being beaten with a jack hammer.first I thought the new transmission was the issue, put the truck up on stands and had a friend engage the transmission and give it some gas... no problem... the had him give it some real gas... bam rattles like crazy... climbed underneath( I know I know, not wise) put my automotive stethoscope to it and nothing. Okay... it's the engine... yup it's the engine. Horrifying sound. So we shut it down and I drain the oil, remove the pan... everything is tight and sound. Hmmm.... nothings broke or loose... looks absolutely great. Wtf? So we put the pan back up after cleaning it up. Move to the top of the motor, remove the valve covers... nothing everything is tight and within spec. SMH... okay compression test... 180PSI all cylinders... now I'm frustrated... looking at spark plugs... brownish coating... running dry... that cant be the carb has smallest rods , largest jets... and moderately light springs... when driving, the truck is eating gas... I know cause I've gone through a tank in half a week. Looking at spark plugs again... plugs dont lie. Okay let's test coil... MSD is putting out 7 ohms... within speck... test wires... wires good... WTH man... am I crazy? What am I missing? I'm running 91 Octane with an +7 octane booster... can I get engine knock that high?
88 Dodge w250 HD Power Ram
360 bored .030
Keith black hyperueretic pistons
Comp springs / Rods
Melling valves
91 swirl port heads ported and polished Int. 2.02 / Exh 1.96
Edelbrock performer air gap intake
Edelbrock 1406 Carb (too small?)
B&M flex plate
PATC Built Viper 2 series A518 46RH
4.10 gearing
35 inch tires
And a cherry bombed dual independent exhaust.