High speed stability issues

So my Valiant ran 131 mph and that was at 6800 through the stripe. I was limited by my 2 step. Tach was out at higher rpms. The car was squirrelly. It is a brick....with a Harwood scoop. I replaced my upper control arms to QA1 units for some stability, but grenaded my 8.75 on the next run. Ready to go back to the track but was wondering if anyone has any suggestions for high speed stability. Lower cover? Cowel style scoop? The nose is already dropped for the 3 inch pan to ground clearance. Skinny 26x4.5x15 front tires ,more pressure,, less pressure? At 35 psi Carb is up higher than the hood line. This is a stock bodied 66 Valiant. No spoilers. I'm thinking my scoop is lifting the front end but I'm not sure. Havent taken any videos of the car at the top end yet. I know this is a lot of dksjunct info but I was hoping someone with an early A body has dealt with these issues before. Any experience anybody?