We refreshed a Koffel built low deck 526(4.375 x 4.375) few years ago that had been run in either a puller or a mud truck(can’t remember which).
It had what I would consider a stage 1 type job(bowls and chambers) on original B1’s.
Easy on parts roller with the original style black Dove rockers.
I guess at some point it had ingested some dirt, and was here primarily get taken apart, thoroughly cleaned, honed, heads touched up, new rings & bearings, and put on the dyno.

It made about 830hp(no inertia correction) with a single 1050 on C12 race gas.

The heads flowed 392/266@.800 lift