On The Dyno

For some reason, the new KRE aluminum heads reminded us of a company baseball game. Imagine you are at yours with all your work buddies and playing that company from down the street. Everyone is having a good time, and all things are pretty much equal. All of a sudden, a new batter steps up for your competitors. Word quickly spreads that he doesn't even work for that company; he's a ringer sent in to win the game. On top of that, he's got better equipment than anyone else. All of a sudden, your just-for-fun sporting event gets serious.

That's what the new Kauffman Racing Equipment (KRE) heads are to the Pontiac world--ringers. KRE is a well-known commodity in the Pontiac hobby. As you may have guessed, one of the company's specialties is head work. From squeezing more power out of iron units for any stock or slightly larger-sized engine to the big ol' nasty 1,900 horse (no, that's not a typo) anything-goes big aluminum versions, brothers Jeff and Mark Kauffman have a handle on producing power. After grinding enough heads to keep themselves cross-eyed for the rest of their lives, Jeff and Mark Kauffman cut straight to the chase and started making their own aluminum heads. This occurred after seeing the need for an aftermarket head with some modern touches that would satisfy street machiners and the weekend racer alike. Creating a new cylinder head is a huge deal in itself but there is more to these new pieces than some just slick CNC work.

When KRE came out with these heads, it raised the bar in the street/strip performance market by not only providing more modern features like a heart-shaped combustion chamber and improved spark plug placement, but also by retaining the stock bolt and port locations and a stock D-port exhaust configuration. This way, they are virtually a bolt-on replacement for factory iron D-port heads from '65-79 (just be aware of chamber-size differences that will affect compression ratio).

They come in two versions that we'll call mild and wild. While the mild versions have plenty of killer flow cast into them, before they leave KRE, they are smoothed out a little (mostly to remove any casting flash or standing seams). The wild versions stay on the CNC machine a little longer, getting a state-of-the-art port job. Even after that, Jeff still puts them on his grinding bench and gives them a little more. Available chamber sizes are 85 ccs and 65 ccs.

Like any new product, KRE is still on a learning curve with these heads, and with each set they run through the process, they get better and better. KRE believed the new "mild" units would deliver at least 20 more horsepower than street/strip ported factory iron heads--perhaps even 25--but the dyno test will tell us more. By the time you read this, the heads will be on the market.

KRE offered Engine Masters the chance to watch as they did some serious R&D on their own product. The plan was to take a proven engine with modified 6X heads, bolt it up to the KRE dyno, baseline the motor, swap over to the new heads (mild versions), and see what the difference was. They would change the heads only but would swap carbs on both setups.

That's because the owner of said motor was Cliff Ruggles, a noted carb guru and owner of Cliff's Q-jets who wanted to test his own product (a modified Quadrajet performance carb) against a Holley. The same intake would be used for both tests, as would the dyno headers (1 3/4-inch four-tube with 30-inch long primaries), distributor, the rest of the ignition system, and the roller rockers. The object of the thrash was to learn just how much more power these new heads would produce over the worked 6X Pontiac heads under virtually the same conditions. We want to stress that those would be the only variances between engine configurations.

Part II of the game plan was to put Cliff's car on the track and get more comparison info. He has raced this configuration in his '73 Ventura for quite a while now, so any differences, subtle or not, would be quickly noted.

The test engine was chosen because it's a proven, consistent product--having served Cliff well for over three seasons. During that time, he has flogged it relentlessly, always keeping a keen eye on just what every little change has done to his highly effective package. Cliff's engine is a 455 that's gone .060 over to become a 468 and was one of the first to use Crower rods when they came out. The 6X heads are worked in the bowl area and have a very good valve job. They were also modified to install larger 1.77 exhaust valves.

The intake is a '68 400 cast iron model. Intake mods are more of a function nature than for performance and are at the flange, so the intake will accept the square-flange Holley without an adapter or the spread-bore Q-jet. Cliff tests each and every one of his carbs on his own car before he ships them. That way he can tell just how they are working under the same conditions. We joke that Cliff's '73 Ventura is his dyno, but the bottom line here is a potent 455 transmitting power through a Turbo 400 and 3.42 gears. (You can check out the rest of the engine specs in the sidebar.)

On the JK&M Custom Flow 400-cfm flowbench, the setting was 28 inches of water. The 6X head flowed 232 cfm on the intake and 196 on the exhaust, and the KRE head flowed 261 on the intake and 220 cfm on the exhaust. All were tested from .100 to .500 lift because the 6X port nosed over after .500 lift, and the aluminum D-port only flowed about 5 cfm more at .600 lift according to Jeff.Kauffman also cc'd the heads using the standard mixture of mostly water and a little alcohol. The 6X heads filled up to 91 ccs while the KREs held 85 ccs. The 468's compression ratio using Cliff's 6X heads is 9.95:1, and with the KRE heads, it jumps to 10.48:1. This is due to the different combustion-chamber size. However, the aluminum head can take more compression than an iron head before detonation because heat dissipates faster from the chamber through the aluminum.

Regarding the valve job, the 6X heads had 30-degree seats on the intakes and 45-degree seats on exhaust with a three to four angle grind. Jeff explained that the 6X can't really fit a full, four-angle valve job, so they usually end up being between three and four in some places. The angles for the 6X intakes are 15-degrees top, 30-degrees seat, 60-degrees under, and 75-degrees bowl. The exhaust angles match those of the KRE head as listed below.

The KRE intake and exhaust seats are both ground at a 45-degree angle with a well-defined four-angle valve job on the intake and exhaust seats. Those angles are 35-degrees top, 45-degrees seat, 60-degrees undercut, and 75-degrees bowl. Ken Criss is the man at KRE who assembles these aluminum heads, and once he has finished a set, the first thing he checks is the height of the valves for consistency. He installed two sets of shims in the heads they used for this test to set the proper spring height of 1.700 inches. When comparing valves, the 6X for this test used 2.11 intake and 1.77s on the exhaust (1.66 exhaust is stock). The KRE heads used Ferrea valves of 2.11 inches intake and 1.66 inches exhaust. When using the KRE heads, the stock head bolts (there are three different lengths) will have to be swapped out for a set of ARP head bolts, PN 190-3605. For our test, once the KRE heads were installed, Cliff would have to ensure the same rockers used on the 6X heads would operate at the correct and most effective fulcrum. He would use a marking pen on the top of a valve stem to see where the rocker was making contact. When it turned out that they were not in optimum alignment as seen by the contact patch being on the edge of the valve, a set of longer Comp Cams pushrods would be used. They are 9 5/16 inches (9.400) long as the geometry of the KRE head's valvetrain is slightly different from the 6X heads. Jeff points out that depending on the rockers used, they could go as long as 9.450.

The KRE dyno is a Super Flow SF-901 with a 2,000 lb.-ft. torque brake. After the discussion about how much power a said part or combination should make, the dyno takes all of the guesswork out of it because it's all right there on the readout--or it's not. Dyno protocol was as follows: pulls were made from 3,500 to 5,600 rpm each time; all pulls were up-sweeps not down-sweeps. Why not start pulls lower than 3,500 rpm? According to Jeff, the problem is the dyno uses so much water on the bottom end during a pull with a big engine that it may run out of brake at the top end and uncouple the engine, giving false peak power readings.

The air/fuel ratio was monitored by the brake specific fuel consumption (BSFC) numbers. Jeff said that he was "looking for figures in the .43 to .50 range to tell us the efficiency is good and the air-fuel ratio will be close from that." He reported that the fuel curve was basically the same yet the KRE heads made more power on the same amount of fuel. This means that they were more efficient.Water temperature for all pulls would be between 170 and 180 degrees and oil would be at 200 degrees. Only 93-octane pump gas was used. There would also be back-up pulls for each pull to substantiate the numbers. The only proposed changes were to the jetting and timing, and even those would be more of an adjustment than a big change as it's normal dyno-tuning procedure to tweak with timing and jets. As it turned out, there were no changes in jetting because both carbs were right on according to Cliff and Jeff.

To settle Cliff's personal carb quest, his Q-jet performed close to the Holley he tested, and the numbers prove it. On the best pull, the torque on his motor, right out of his car and still using the 6X heads, was 522 lb.-ft. at 3,900 rpm with his carb and 528.3 at 4,000 rpm with the 850-cfm Holley. Horsepower was close with 455.4 with the Q-jet and 449.7 with the Holley. It pretty much confirms Cliff builds a great Q-jet. In subsequent pulls, timing changes either way showed no increase in power. So, with the baseline set, off came the 6X heads.

As the KRE heads went on, everyone was getting stoked. It was an exciting time for the brothers Kauffman and proudly, Jeff said the motor is, "looking better already--getting rid of those ugly blue heads." When everything was ready and the first pull was made on the KRE heads, it became apparent that the new combo was creating more torque--MUCH MORE TORQUE. The reading was 548 lb.-ft. at 3,600 rpm. Jeff said, "It needs more brake." So he added 5 percent more brake to the dyno and tried again.

On the second pull, the dyno read 485 horses at 5,400 rpm with 550 lb-ft at 3,800 rpm. That's an increase of 35 horsepower, and the motor is still at 30 degrees timing with the Holley carb. It's only the second pull, and there's more coming.

The next two pulls were at 32 degrees, and both had problems with the amount of brake taking on the new torque and holding until the top end. The power levels stayed pretty much the same, but the boys still wanted a definitive reading. Jeff noticed the power curve at the low and mid range, even with the brake glitches up top, and described it as, "flatter and smoother." They finally got a clean one at 32 degrees of timing but saw no power improvement. Cliff backed it down to 30 degrees, and they tried again. The engine hit 494 horses this time but Cliff said, "It didn't sound right." Jeff answered, "That's because it ran out of brake again. Another adjustment sets the brake as needed.

Then, with the Q-jet swapped on, the best power numbers were 494.2 at 5,400 rpm and 549.5 lb.-ft. of torque without running out of brake. Comparing the two best Q-jet-equipped runs (see charts) reveals an increase of 38.9 hp with peak power moving from 5,300 to 5,600 rpm and an increase of 26.6 lb.-ft. of torque when compared at the same 3,900 rpm for the KRE heads.

With the hard numbers from the dyno collected, the only remaining truth is the difference in price. If KRE were to build a state-of-the-art set of 6X heads for a customer that would flow about 240 cfm on the intake, including the cores, all the parts, and labor, the price tag would be about $1,400. Off the shelf and ready to bolt on, the new KRE heads cost $1,950. This prompted Jeff to say, "When can you spend $500 and pick up over 35 horsepower?" When indeed. Advantages and disadvantages are simple. Factor in the above price differential, take into consideration that the technology you are buying is today's and not 30 years old, and add the aluminum-over-iron factor of better-cooling properties and weight (just 31 pounds each for the KRE heads), and you've got a start. Then realize that the engine has the potential to run better with unleaded gas at a higher compression ratio than factory iron heads, and the aluminum heads more effectively prevent detonation. And did we mention more power? Put these ringers on your team and start looking for the wins to come.

The heads were compared on a JK&M Custom Flow 400-cfm flowbench. Testing was performed at 28 inches of water.
6X Iron HeadKRE Aluminum Head
The heads were tested on a 455 (now 468) engine mounted on a Super Flow SF-901 dynamometer. Jeff usually does not acknowledge the torque figure at the start of the pull because it could be incorrect. So the reading was taken at 3,900 to get a more realistic number on the 6X head pull. The correction factor for testing was 1.083.

Block: .060-over 455 = 468 ci
Crank: Stock nodular iron, 4.21 stroke, rotating assembly balanced
Rods: Crower forged steel, stock 6.625 length
Oiling System: Stock
Pistons: TRW forged, flat-top, exactly-zero deck
Compression Ratio: 9.95:1
Heads: 6X, 2.11/1.77 valves
Mods: Port-matched, cleaned up, bowl work, bigger exhaust valves
Valve Job: Custom, multi angles
Chamber Size: 91 ccs
Head Gasket: Fel-Pro 8518
Rocker Arms: Crane, 1.65:1 roller, Rhoads lifters
Cam: Crower PN 60919, hydraulic
Duration at .050: 231/240
Lift: .517/.517 with 1.65:1 rockers
Lobe Separation Angle: 113
Installed Position: Intake set at 109 centerline
Intake Manifold: OEM '68 cast iron
Mods: Reworked at carb flange to fit both bolt patterns, Q-jet and Holley
Carb: Q-jet, .073 primary jets, .048 custom-machined secondary rods
Carb: Holley, custom .093 primary jets, custom .097 secondary jets
Distributor: GM HEI, 20 mechanical advance
Timing: 30 total, all in by 2,500 rpm
Spark Plugs: AC R45TSX

AT THE TRACKPart II: From The Dyno to Dragstrip

We priviously introduced you to the brand-new aluminum D-port heads from Kauffman Racing Equipment (KRE)--which were designed to be high-performance street/strip alternatives to finding factory iron cores--and had them ported and completely rebuilt. These heads were developed to be a direct bolt-in replacement for '65-79 cast-iron factory D-ports and have many innovative features that were discussed in detail earlier.

Engine Masters was invited to observe as these new heads were tested against a set of 6X heads on the same dyno on the same engine, which happens to be a 468 cubic-inch (455 +.060) Pontiac out of Q-jet-builder Cliff Ruggle's '73 Ventura. The idea was to see the difference in results with the only change being the new KRE heads; everything else would remain the same, and testing would be done on the same day under the same conditions. Actually, the only variance was a sort of test within a test. That's because Cliff owns Cliff's Q-jet, and he wanted to test his Q-jet carb against an 850 Holley using his cast-iron intake that he modified to accept both carb's flange styles. However, before/after comparisons will only be made with the Q-jet in this story.

Cliff's 6X heads had been reworked, including bigger 1.77 exhaust valves, port matching on the intake side, and bowl work. They had 91cc chambers resulting in a 9.95:1 compression ratio. The 6Xs flowed a maximum of 232/196 cfm at .500 lift at 28 inches of water on KRE's flow bench compared to 261/220 cfm for the KRE aluminum D-port heads. These were the basic KRE heads, not seriously ported but merely cleaned of burrs and seams and then port-matched to the intake. KRE offers its heads in two versions, with the second one getting a longer ride on the CNC machine (resulting in even better flow).

Jeff and Mark Kauffman bolted Cliff's 468 Pontiac to the dyno, and after a couple of pulls, got a baseline of 522 lb.-ft. of torque at 3,900 rpm and 455.4hp at 5,300 rpm with the 6X heads and the Q-jet carb. With the baseline set, the old 6X heads came off, and the spanking-new KRE aluminum versions went on. KRE changed the heads only, still using the same carb and intake. The best pull of many revealed 549.5 lb.-ft. of torque at 3,600 rpm with 494.3 hp at 5,600 rpm.

The price for this performance was $1,950 for the KRE heads ready to bolt on. Jeff Kauffman explained in Part I that he would charge about $1,400 to build a set of 6X heads that flowed like Cliff's did (including the cores). So for $500 more, you can purchase the KRE aluminum heads and get over 35 more horsepower and cut weight at the same time.

But this new set of heads wasn't designed just for dyno pulls. Jeff and Mark Kauffman are hardcore Pontiac guys and wanted to know more about how their new heads perform at the track. The next step in the test was to return the motor to Cliff's '73 Ventura and make some passes on it. And that's where we pick up this month.

Prior to the head swap, Cliff's Ventura, with its 6X heads, was a consistent 12.30-12.50 piece. His best ever e.t. was a 12.10 with a speed of 111.96 that was, in part, attributed to running at sea level at Virginia Motorsports Park.Once he reinstalled the engine after receiving the new KRE heads, it was time for the first test session at Norwalk Raceway Park. The year before, the 6X head combination in the same Pontiac on the same track with the same driver ran 12.41 and 12.42 at 110 mph with a 1.77 and a 1.78 60-ft. A year later with the KRE heads installed, Cliff was ready to go but described the day as "an unbelievably hot one of 90-plus degrees with very high humidity." Even so, he ran an 11.91 at 113.65 mph, a great improvement. One more run that hot day yielded a best-of-day 11.81 at 114.20 mph. Again, the configuration he used was the exact same iron intake and same '78 Pontiac reworked Q-jet carb used in the dyno tests.One or two runs do not make conclusive evidence, so more testing was still needed. Besides, Cliff felt there was more to be found. He had to get used to this new package and explore the nuances of it.

It wasn't until the Ames Performance Pontiac Nationals at Norwalk Raceway Park later that same week that the chance came for Cliff and the Kauffmans to finally put together a bunch of runs. The weather had improved with temps dropping to the 80s, but there was still a head wind to contend with. The Ventura ran consistent 11.80s at 114 mph with 1.67-1.69 60-ft times during the three-day event, and Cliff had even won the Stock class.

On the last run of the weekend at 8:00 p.m. on Sunday, with the temperature dipping to the low 70s and the headwind gone, Cliff was in the semi-round of King of the Hill. Though he redlighted, he took advantage of the cool night air, wrung it out to 5,600 rpm before shifting, and cranked out an 11.79 at 114.49 mph--marking the quickest pass yet for the new combination. Cliff says the higher shift rpm (he had been shifting at 5,000 rpm) didn't make the Ventura go quicker; the head wind dropping off and the lower temperature were the real factors.

According to Cliff, "It has more power than I thought it would. You can feel it make more power everywhere." He's also noticed better idling due to the now-higher compression, and it's now smoother coming off that idle. Overall, the engine heats up to operating temperature quicker but doesn't run hot. Cliff looks to keep on tweaking it and realistically sees dropping e.t.'s into the 11.50s.

From 12.41 at 110 mph to 11.79 at 114.49 mph shows that the dyno did not lie and, in fact, these KRE aluminum D-port heads do make impressive power as compared to the modified 6X heads. With the old heads and a half-tank of fuel, the race weight with driver was 3,805 lbs. With the KRE heads and a quarter-tank of fuel, race weight is 3,760 lbs.

As we said from the beginning, these KRE aluminum D-port heads offer a more modern design than traditional Pontiac D-port iron heads, make more power, and weigh less. We have presented our story; the rest is up to you to decide if KRE's heads are right for your combination.

Model of Car: '73 Pontiac Ventura
Race Weight: 3,760 lbs
Converter Stall Speed: 3,400 rpm
Transmission: Turbo 400
Rear: 3.42:1 Safe-T-Track
Slicks: Mickey Thompson ET Streets, 11.5x28, Tread width 8.6"
Launch Technique and RPM: 1,400 rpm
Shift Points: 5,000/5,600 rpm
RPM at the Traps: 5,100 rpm
60-ft Time: 1.67-1.69
1/8-mile Time: 7.49-7.52
1/4-mile Time: 11.79-11.86
Trap Speed: 114.49

Block: .060-over 455 = 468 ci
Crank: Stock nodular iron, 4.21 stroke, rotating assembly balanced
Rods: Crower forged steel, stock 6.625"
Oiling System: Stock
Pistons: TRW forged, flat-top, zero-deck
Compression Ratio: 10.48:1
Heads: KRE Aluminum D-port
Valves: Ferrea stainless, 2.11/1.66
Valve Job, Intake, and Exhaust: 35* top, 45* seat, 60* under, 75* bowl
Chamber Size: 85 cc
Head Gasket: Fel-Pro 8518
Rocker Arms: Crane, 1.65:1 roller, Rhoads lifters
Valve Springs: Crower PN 68405, 1.700 height
Seat Pressure: 115 lbs
Open Pressure: 310 lbs
Pushrods: Comp Cams 9.400
Cam: Crower PN 60919, hydraulic
Duration at .050: 231*/240*
Lift: .517/.517 with 1.65:1 rockers
Lobe Separation Angle: 113*
Installed Position: Intake set at 109* centerline
Intake Manifold: OEM '68 cast iron
Mods: Reworked at carb flange to fit Holley flange (without an adapter) as well as Q-jet
Carb: Q-jet, .073 primary jets, .048 custom-sized secondary rods
Distributor: GM HEI, 20o mech. adv.
Timing:30o total, all in by 2,500 rpm
Plugs: NGK R5671A-8
Exhaust: Hedman 4-2 Headers 1 3/4" primaries, 3" collectors, 3" H-pipe, Flowmater 40 Series mufflers with 3" inlet/2 1/2" outlet, full-length compression-bent tailpipes

20579 Berry Rd., Dept. HPP
Mount Vernon
OH  43050
Kauffman Racing Equipment
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