Blocks don't matter a hill 'o beans... they are ALL the same for purposes of this build.
IMO,
And sry to rain on the parade.... but you are NOT ready.... and you have insufficient information/data for patent Camshaft profile selection at this point..... given the intended application, ie:
* Auto/2500
* 28" Tire on 3.55's
* Dual Quad / Dual Plane
* Cast Iron heads
At this point you might as well turnaround and throw a dart at the Cam book ?
What's the actual Compression ratio ?
Fuel being used ?
You require:
* an actual Piston TDC Measurement/CC Volume installed in the Block, because WISECO Pistons are typically built generously DOWN from advertised at TDC ..... and it is Not uncommon to install WISECO's thinking they should be .010" or .020" down and find them closer to .030" or .040" down
Are they indeed WISECO's ? or Pro Tru Pistons made by wiseco ?
* an actual CC Volume on the 915 Iron Heads because those as well can be all over the map
* Head Gasket being used
* Valve Sizes being used in the 915's.... even better would be some Flow data ? but I get that ain't happening... no matter, even Valve Sizes will help.
From the above 3 things you can then begin targeting cylinder psi/efficiency in the high torque Cam profile application.
* Headers ? Manifolds ? WHAT ?
Look.... spending some time now can reap GREAT rewards later far beyond just throwing a Dart at a Cam page ?