I originally asked my builder to supply and install the KBs per the book because I was gung-ho for the predicted results.
but that engine ran hot no matter what I did, and would lock-up everytime I shut it off, and it got terrible fuel mileage, and required a lot of throttle to keep it idling.
Before long I pulled it out and tore it down to see what the builder had done.
Well, from memory; the skirt clearance was .0025 to .0030 and the ring gaps were tight, as per the KB book. I was very disappointed at the "large " skirt clearance, but there was no indication that the pistons were sticking, so I assumed the rings were the problem. Again, no damage.
So I sent the block to a different machine shop to even out the bores. And it came back at .0035 every one the same now, and pretty straight. Yes on cold mornings I sometimes hear a lil rattle.
I threw the cast rings away, in favor of Plasma-Moly file-fits, and opened up the gaps to the towing/ nitrous specs of .034/.024 IIRC.
Everything else looked good so I bolted it, Edelbrock heads and all, back together.
With no other changes, all my problems were solved. ALL OF THEM.
So I experimented with increased coolant temp, and found that she liked 207* at the stat-house. And she, by seat of the pants, had no preference to timing in the window of 32 to 36, so I set it to 32 for that summer. The next summer I set it to 34, which made no discernible difference in power. And she has run in that 32 to 34 window ever since. I run it on 87E10 exclusively.
I have not had any heating problems since those changes were made. and she goes like a cat on fire. Even 93mph in the Eighth, at 3457 pounds, at 930 ft elevation.
I would use KBs again, but I would try a lil less skirt clearance next time, and a lil more cylinder pressure, but
I will not use either of the previous machine-shops again.