Older Engine Power Figures

As of recent I've been sitting here trying to create older 1960's engines like the good old 406 cid ( 6.6L) But I've ran into a few problems, not sure if it was developer oversight, or just you know something you guys are going to work on but here is my question.
Will I be able to replicate them at least within 10% of what they should be ?
As of current I can't even get their RPM's past 5000 and that is with adding every slider high, which just leads to crazy man hour requirement... Which makes no sense since some of the older engines such as the engine in the 1962 ford galaxie which used a 406, was able to rev to 5800... but with even a DOHC ( it was a pushrod set up ) and cams set crazy, it is impossible to reach accuracy with it. So I just question will I be able to.. thank you for taking the time to read this as well guys, but anyway great work, keep it up look forward to seeing it completed
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Will I be able to replicate them at least within 10% of what they should be ?
As of current I can't even get their RPM's past 5000 and that is with adding every slider high, which just leads to crazy man hour requirement... Which makes no sense since some of the older engines such as the engine in the 1962 ford galaxie which used a 406, was able to rev to 5800... but with even a DOHC ( it was a pushrod set up ) and cams set crazy, it is impossible to reach accuracy with it. So I just question will I be able to.. thank you for taking the time to read this as well guys, but anyway great work, keep it up look forward to seeing it completed
