suspension question

[1978chev]

hey guys i have a 69 c10 just installed a complete suspension system from cpp i got the tubular control arms upper and lower 4.5 drop in front with spindles and springs have a total of 7in drop in rear 5in springs 2in blocks with shock relocaters in rear new shocks all the way around and front and rear sway bars and the adjustable pan hard bar
i have 20's front and rear 245/40 on front and 275/40 on rear

my problem is on most roads the truck is very twitchy i have aligned it a couple times.front end is tight has all new tie rods no play at all (a little in gearbox but my daily driver has more play than this thing) the alignment is good camber is -0.2deg on both sides and caster is around 4.5 deg posative thrust angle is 0.17 any one have any suggestions