Cliff and I agree to disagree on a few subjects. We ARE old friends, but we have completely different approaches to certain aspects of engines. I'm not interested in debating who's "right" and who's "wrong". He's a carb guy and I'm a motor guy. My point is practicality, not "pressing the edge". If you're willing to go through the tuning and care the higher compression needs, and the 5 or so HP you MIGHT gain from it is important, by all means, do it. The vast majority of hobbyists and even racers, are much happier building it to a practical point, rather than a "max" point. Think about it. If you already have 400 HP, do you need the headaches of constant attention to the tune to get 405 HP? And, God forbid, what if you're on a trip to California where you can't BUY 93? Only 91?
We've learned through experience, "flow trumps compression". That is, porting the heads to flow better will make more usable power than raising the compression. We routinely build 600 HP "pump gas" engines without pressing the limits of the fuel, that people drive every day. This goes against "old school" thinking where compression was "king" (probably a Chevy-related myth).
"Quench area" is defined as places in the chamber where the fuel mixture can "hide" from the burn. It "puts the fire out". Zero-decking an engine "on the edge" is good because it reduces turbulence in the chamber as the mixture is compressing. Reduced turbulence translates to less "friction heat" among the molecules in the mixture, thus reducing the tendency to detonate. When we "zero-deck" (CVMS), we usually keep the piston .005" "in the hole". The benefits of reducing quench are realized, but the chances of the piston "kissing" the head is drastically reduced. One missed shift is all it takes to rev so high so fast, the piston can hit, pushing the oil out of the rod bearing when it needs it the most. This ins't a "hard fast rule", but a policy. As another mentioned, it's part of my job to protect some folks "from themselves". We seldom consider warranty issues when designing an engine for a customer.
Pistons more than .015" "in the hole" (deck clearance) cause more of the flame "front" to be exposed directly to the cylinder wall, putting more heat into the top of the block. If all conditions are "good", the burn is "over" by the time the piston moves more than a few degrees "down".
The 4-7 "swap" is a good thing, almost without exception, for Chevys, Pontiacs, Chryslers, anything with the "traditional" firing order and cylinder "layout". It redistributes the power pulses to be a little more efficient, as well as moving some of the torsional load on the crank from the weaker "front" to the stronger "rear". Power output and longevity are both improved. This is not an opinion.
LSx is a completely different design, sharing ZERO architecture with previous small blocks. It much more closely resembles the Ford "Windsor" small blocks (289, 302, 351W) as far as layout and valve spacing. The firing order is not similar to any of them. The only two part numbers found in LS1 that were used in small blocks are the rod bearing and the hydraulic roller lifter, both of which are used in other modern GM engines as well.
I hope this helps clear up some of the technical issues being discussed here.
