[jim_howard_pdx]

Andy I did not mean to ignore you.

I hate to give away all my secrets. I should probably send you a personal email, but since I have openned up the can of worms I might as well see if they are tasty.

You typically have some type of deck heightwith every block out there. This is not accidental. As you rev up, and as the combustion temperature rises the pistons and the rods grow. So the deck height is calculated to absorb that growth, and any slop that happens as your main and rod bearings wear.

For instance on my street rod 358, my deck height is .017 inches and my compressed gasket is .039. So my quench area would appear to be ideal at around .056. Very close to the minimum .080 quench I reported.

BUT I OVERSIMPLIFIED TO SEE IF ANYONE COULD CATCH THIS, and you may have figured it out in a roundabout fashion.

Good job!

On my 9.2 et bracket engine, I reduced the deck and gasket quench to .044. I couldn't make it tighter, just trust me on this. It is way too complicated to explain how we determined the bare minimum for this response.

If you are running aluminum or titanium rods, these grow much longer than forged steel rods. You need to take all this into account.

I try to get the dome of the piston to fill as much of the wedge as I can, as I start the process of shaping the piston top. The valve reliefs make you do some strange contortions to keep the piston top smooth. That is why I like to use blanks, and cut exactly what I need to get my piston to valve clearance handled.

Then you have to measure. Check with clay or displacement media. My favorite was a type of silly putty they use for stroke patients to stregthen the peoples grip.

When I take my first measurements my compression starts at about 13.75 to 14.25 compression. Way high for my tastes unless you are running Alcohol. Then 14 to 1 is perfect. You can stop right there.

Since I like to polish my combustion chambers I often work the chamber a bit to get the reduction in compression ratio and work to establish that .080 space from the dome to the wedge.

Polished combustion chambers NEVER make more horsepower or torque. I could just remove all the rough goobers and that would be fine but NO. I have to be anal retentive about it and polish the thing. I am a NUT. I admit it. Everyone who knows me well would agree.

I try to give myself a generous wedge area at least 1 inch surrounding the spark plug tip. 1 1/4 to 1 1/2 is great. So I take the 0.10 measurement as the most gap around that 1 1/2 inch wedge and then taper it gradually reducing to the .044 quench at the deck.

There you have another secret. Keep things open around your plug, and tight at the piston edges.

So Andy has in a round about fashion, found one of my trick points I was using to test you. I figured someone would say if .080 is ideal, why wouldn't .050 be even better.....

Why not run it ultra tight, remember that the air fuel charge has to be very dense and thick right around the spark plug or the mixture will not ignite properly and the flame will not propogate smoothly across the piston like you need.

So you need that wedge effect going for you at the plug and you need to go from wide to thin as you move away from the piston center.

Then I go for the dang longest rod that can be shoe horned into that cylinder. I have had journals cut down to weirdest sizes just to get an extra .10 to .30 rod length. If you minimize your quench, have a smooth surface to burn across, and sit the piston at top dead center as long as you can keep it there, your torque will be a brute.

Anyone ever own or race a 455 Stage Ior Stage II Olds engine?. They ran 475 hp and roughly 575 ft pounds of torque. These were factory long rod engines that you could buy, drive to the strip and take home your trophy. It took us a while with 390 Ford engines to keep up with these. Actually it took a 427 side oiler or a 428 to do one in. When the 429 SCJ hit the market, the Olds guys really got left in the shade. You were running a massaged Rat a Wedge or Hemi Crysler or a 428 or 429 CJ. The others took a back seat.

If you can get away with it, and you have to be really careful, you should see if you can reduce the overall deck quench to about .044 on your engine running a quality Rod. Add some clearance if you are running aluminum or titanium. So leave yourself some clearance for rod growth and bearing wear on the mains and the rods.

So who will find my other tests.......

The race is on!