What camshaft spec for 425 hp

If it were me, i would put a serious camshaft and convertor in the car. Those two things alone( assuming you run either a shorter tire or more gear) should get the car in the very low 12’s. At least.
My car started out not unsimilar to yours. Bone stock 360, stock eddie heads. 750, m1 single plane, 4500 8 inch vert. 4.10 gear, 727, 240ish@50 comp solid cam. 275 bias tire..28 by 10
Ran 12.23@109 first time i ever took it out.
Swapped to airgap, 5000 vert, 260/264 Howard solid, minor porting of heads( stage 1 type deal) milled heads 30 thou and ran 028 head gasket to up compression on the 360 to get it around 10 to 1
Couple outings after the above changes…11.26 @ 118.40.. typically in the 11.40’s to around 11.50 in summer air.
Cam and convertor are everything in a stock stroke smallblock….at least its always been what i key on. Mine was/is a street strip car as well