[jim_howard_pdx]

Honestly, I would send back the AFR heads all together. Tell them you want your money back, and that you will tell ALL your Ford racing buddies about the way you have been treated. They are an arrogant bunch of monkeys.

My Trick Flow twisted wedge heads are pocket ported to the 1261 felpro gasket set. That is 1 7/16 wide by 2 1/4 inches tall. The only problem I had with these heads was that they would suck in the felpro ruberized paper gasket. Felpro is now selling an improved 1261S gasket. It is a stiff plasticized material that will not shear and suck in. It is teflon coated to allow you to pull your intake over and over again. I really love it so far, but I have yet to run the car at wide open throttle yet. I have got to get my ignition curve corrected so I don't go detonating and spin out another rod bearing.

My heads are now cc'd at 198 cc. They flow 249 cfm at 520 lift on the exhaust, and flow 304 cfm at .498 lift on the intake. This is way better than the 185 AFR. You would have to use their 205 units just to equal these numbers. By the way these figures are WITH simulated backpressure from intake and exhaust systems.

Many shops just report the cfm from the the direct ports without consideration to backpressure. This is cheating. An engine could never flow that with the exhaust and intake hooked up.

Listen up, Here is my speed secret for today.....

Back in the 70's we used to always buy high dome 12.5 to 1 pistons, machine them for the cam lift- valve clearance we needed and then used a dye grinder to totally smooth the remaining surgace of any edges that could radiate heat. At wide open throttle most of your metals are glowing, so cutting down any surface that could cause detonation will get you more reliability and greater power. We cut the dome smooth and removed enough metal to produce 0.08 quench with the compressed gasket. We shot to never have any area across the combustion chamber have more than 0.10 quench area. To do this we angle cut the heads sometimes as much as a quarter inch to reduce the wedge. We only needed enough wedge to have consistent and radial burn from the spark plug kernal to the piston edges. Running .080 quench was ideal.

That meant we had to machine the head bolt faces to reestablish square, and we had to counter angle mill the intake manifold and carefully line it up for proper port indexing.

When piston coatings first came out, we would coat both the entire surface of the piston and the entire top of the dome. We tried coating the valves but it did not affect HP whatsoever. We were using mostly SS and Titanium valves depending upon the use of the engine, and they did not seem to affect HP or torque But piston and combustion chamber coatings made a big difference. Often we could run an additional point of compression. Going from 11 to 12 to 1 compression was worth almost 30 horsepower on a 383 small block.

This is a good secret to share with you guys. Run a dished piston with less quench when you are building for torque, like you off road truck fiends, or you boat racers. Run a tight quench when you are after higher horsepower.

I do not know all the physics on flame travel under velocity and compressed combustion, but to keep things simple the flame travel is broader, slower, and the fuel burns more complete when you keep the quench area really tight. I learned that from watching a Smokey Yunick engine being torn down after winning its bracket at the Winternationals. I wish I could have taken pictures of that combustion chamber and piston top for you to see. The burn was from spark kernal to the extreme edge of the piston tops and there was no area of any piston that showed slow or incomplete combustion. That Smokey Yunick was a racing GOD. The man was a real genius when it came to making horsepower.

Anyone who has ever raced a Chevy knows who Smokey was. I also stole another of his race secrets. You can often pick up a tenth to three tenths of a second ET time just by equalizing the power among all 8 cylinders. It is much harder to do this than you think.

Most shops will cc each combustion chamber the same, they will cc each port the same, and then when the engine runs EVERY cylinder will build a different power profile.

Why? Because air and fuel do not like to bend and move around port opennings, valve pockets, or curved intake runners especially when each runner shows the fuel a different angle than the others.

The effect of the fuel movement from venturi booster to the piston cylinder walls are different for EVERY stinkin cylinder. The rich cylinders will produce both lower torque at every rpm range, and less total HP. The lean cylinders will show higher torque over some of the range but lower total HP. The optimum cylinders will show what we are all trying to accomplish. Excellent torque at all rpms and high top end HP. When you put it all together, you are sacraficing about 15 to 20 horsepower on a 383 stroker engine. But worse of all, all the changes you make to improve your ETs actually make the difference between cylinders greater.

To get each cylinder right, you may need to enlarge the cc's on some ports. To correct for intake flow patterns, you can use the holley venturi boosters with tabs to correct fuel distribution to the intake ports.

One of Smokey's best secrets were to run 1.6 rocker arms on the lean cylinders and 1.5 on the optimum cylinders. On the rich cylinders he would correct with venturi booster tabs.

For those of you with sequential direct port fuel injection, you can run the rich injectors on the lean cylinders and the lean injectors on the rich cylinders. Take your injectors off, take them to a shop specializing in cleaning and indexing. They will flow rate each injector for you. When you are done you will be amazed by how much smoother the engine runs, and how it feels like there is a hand pushing the car from behind.

To confirm that each cylinder is running equally, you start with plug reading. This is not easy to do with pump gas and all the additives they use to reduce pinging. I would run some 106 racing fuel to do the plug reading. If you are racing, then just pull the heads after every racing session. Look at your piston tops. We would do this just before every final.

I like to take temperatures at the first bend of each primary header tube at about 4500 to 5500 RPM after you sustain that RPM for at least 2 to 3 minutes. This will tell you which cylinders are lean and rich. On the dynos, we would use an air/fuel meter on each exhaust port, and read the port temperature. Even with this type of excellent measurement, you still do not know just how hard it is to equalize every cylinder. Engines are a curious mix of twisted snaked intakes and exhausts. And no two intake castings are ever alike. So remember that EVERYTHING changes when you increase your fuel pressure, or change manifolds or change jets or the like.

Even when we had things as good as we could get them on the dyno, we would sometimes add a little extra valve lash at the track if we found an exhaust port that was cooler than the rest. By slightly reducing the intake valve openning we could match the cylinders to the actual track conditions.

So now you know one more secret that adds up to consistency. You may look funny and get laughed at as you run your engine loud and hard and probe each header tube with a temperature probe. But they will not laugh as you pick up your trophy, they will just say, man I wish I knew what he was up to.

I hope this helps all of you realize just how complicated and exciting quench can be!

Go quench safely out there.