Searching for a factory 340 1970 camshaft!!!

Why can't you use a Comp Cams p/n 20-309-4? Magnum Muscle, 268AH-10
Factory Replacement. Factory I.D. #2899206 for 340 c.i., 1968-71, factory 275 hp
340 c.i.; 1970, factory 290 hp 340 c.i.; 1972-73, factory 240 hp. 20-309-4 - Magnum Muscle These cams follow the tradition of COMP Cams® excellence and offer a step up from original equipment cam designs. Yep, the numbers are not "exact", but close enough?

Then there is Comp Cams p/n 20-212-2? "High Energy™, 268H Replacement for H.P. 340 & 360 4bbl Motors": 20-212-2 - High Energy™ Hydraulic Flat Tappet Camshafts