A low deck 4.25 stroke with a 6.535 rod has the same rod ratio as a typical 454 Chevy 4" stroke/6.135 rod.....countless thousands of production motors went millions of street miles....and every weekend thousands of bracket racers still run the .060 over 468's turning a LOT more RPM than 6500 reliably.

On an RB you can put a fairly long skirt on the slugs since the rod can be longer. On a B with a nominal 9.98" deck the skirt is more limited but still well more than adequate to ensure reliable street service