Billet Ford Cylinder Head Power

[DavidVizard-GFN]

A look at what is probably the ultimate evolutionary step in small block Ford cylinder head production

Text, photos and drawings

By

David Vizard

Complex shapes, and cylinder heads with cooling jackets certainly fall into such a category, are traditionally thought of as being made from castings. That’s an almost universally accepted fact by almost every one except Ultra Pro Machining’s Don Losito. As racers we all like to believe we think outside-the-box to get some technological advantage over the competition. The reality is that very few people actually do think outside-the-box. But let’s not dwell on the thought processes of the average racer here. Suffice to say that to be consistently successful, racing, by its very nature, needs to have a higher mental input than any sport that immediately comes to mind. That being the case you have no doubt already mentally framed the question as to what possible advantages are brought about by making a head from a solid block of material instead of the time honored method of casting it. Since that is as good a place to start as any let’s look into that aspect of the Ultra Pro Machining billet small block Ford cylinder head.

So why the fancy lead shot of the subject of our feature? Well at a first look this head, carved from a sold block of aluminum, really looks the part of something out of the realms of science fiction.

Castings Vs Billet

Although by far the easiest to accomplish, building cylinder heads, especially in numbers, by the casting method is a mixed blessing. On the positive side producing a cylinder head by means of modern castings techniques allows a near net form to be produced. The most obvious advantage here is that there is less metal to remove by subsequent machining processes and therefore production rates are faster and the finished product less costly. Equally of importance is the fact that a casting allows the production of a head with a normally in-accessible water jacket. On the negative side the production of casting patterns requires a great deal of skill and time. This means if just one or two heads are made the cost is very high. Although initially expensive, once made casting patterns do allow the production of a lot of head castings. When the cost of the patterns is spread out over say 500 pairs of heads the cost of the patterns begins to be only a minor fraction of the cost of production. Aside form initial costs the down side of castings is that the cast material is not as strong as it’s wrought billet counterpart by a big margin. Also once you have a casting you are stuck with porting parameters dictated by the water jacket and the existing port shape/positions. All this is apparent to anyone who is seriously into cylinder head design but at the end of the day few cylinder head designers ever contemplate the production of a head by any means other than casting. Don Losito, the boss at Ultra Pro Machining is an exception.

Don Losito and his small but select team of cylinder head specialists are best known within NASCAR circles as the motivating force behind the design and development of the highly successful D3 NASCAR Ford head. From Ford produced castings Don’s company machined and supplied the entire front running NASCAR Fords but the raw casting continually presented both production and development problems. As a result the best part of 6 months was spent prototyping a water jacketed billet head.

From any angle the Ultra Pro Machining billet head is an impressive piece. Although it looks heavy it is in fact just a pound or so heavier than a fully machined D3 head.

The production of a billet head with a water jacket is a complex machining exercise. Even though the use of aluminum and its high heat conductivity makes things a little easier the cylinder head water jacket for an engine that must run wide open throttle for extended periods must be such as to avoid hot spots. Here Don Losito has managed to incorporate comprehensive water jacketing of the normally problematical areas. This was achieved by a simple but effective method that comes under the heading of ‘proprietary technology’. After the water jacket had been completed by the process used all the remaining surfaces that require to be machined are accessible.

Ignoring costs for a moment the advantages of a billet head are many. Starting with a blank (solid) block of material means that any changes in ports, chambers and water jackets are as easy as making the requisite CNC program change. This gives a design customizing capability far beyond that of a cast head. In addition to this the head is significantly stronger due to the nature of the raw material involved. Our rough estimate, which is probably well on the conservative side, would suggest that the billet head is at least 50% stiffer than an equivalent cast. For all practical purposes that puts it into another league altogether. With the sort of boost pressures and nitrous loads we are seeing in what is essentially a 4 head bolt per cylinder arrangement the added stiffness is a much needed asset for those all out engines.

From the color reflection it can be seen that the UPM billet Ford heads intake is substantially a straight shot to the bowl area. Once the bowl is reached the form needed to make those big flow numbers becomes far more complex and subtle changes can make big differences.

Intake Port

Although the increase physical strength of Ultra Pro’s advanced head design will allow the production of more power via boost its real advantage is seen when port designs are considered. As may be expected from a head shop that works primarily with top echelon teams in both circle track and drag racing Ultra Pro is engaged in extensive ongoing R&D programs. This Don Losito considers vitally important if their front running position in competition is to be sustained. Evidence of Ultra Pro’s total commitment in this area is the impressive successes they have had in ProStock over the last five years. All the airflow and dyno test experience garnered is highlighted when the heads are flow tested. Although available with valve sizes from 2.160 to 2.250 for the intake and 1.6 to 1.625 for the exhaust there was only the opportunity to do a quick test on the biggest valve variant. The test was done on a bench that I was the last to calibrate so you can take the numbers as within about 1%. On the intake the flow reached 457 cfm at 0.850 inch lift with a fat curve all the way up to that figure. How fat? Fat enough to hit the 200 cfm mark at 0.250 lift and, on my regularly calibrated bench, I have never seen a figure that high for a small block head.

The cant on the intake port was just one of many factors that allowed a smaller, higher velocity port to get the business of producing power done more effectively.

The swirl generated by the Ultra Pro Machining Ford head was also measured and found to be strong. On the subject of swirl there is some controversy within the race engine community as to whether swirl is a good or bad thing. Some successful engine builders claim that too much swirl centrifuges the fuel out on to the cylinder walls. My take on this is that if this is happening and power is lost as a result it could be that the fuel is inadequately atomized and the result is that the fuel is too readily dumped on the cylinder walls if a lot of swirl is developed by the port. Like many things too much is just as bad as too little. Based on previous experience the swirl looks just about what is needed in a 9000 rpm race engine.

Another factor well worth highlighting is the heads port cross section. The big flow numbers were achieved with a port cross section much smaller than might normally be expected. This results in a high port velocity and that is a key issue toward ramming the cylinder at the end of the intake stroke. Cylinder heads that promote this effect almost always prove to have a far wider power band as well as more top end. Best yet all this comes about with an ability for the engine to hang on longer after peak power rpm. For the drag racer this means holding a lower gear longer which always has a far greater effect on cutting ET’s than adding power alone. For the oval track racer the wider power band means the rear end gear can be made lower for more punch off the corner.

There are many subtle features of this combustion chamber that contribute toward the production of high output. First not it’s compact form. This is good for a fast burn. That factor alone cuts any tendancy to detonate to a minimum.

Exhaust Port

With the big numbers seen on the intake the exhaust on a head such as this will need to flow really well if for no other reason than to get a substantial amount of spent charge out. The measured numbers certainly were impressive. At 0.850 lift the exhaust port of Ultra Pro’s trick billet Ford head bettered 290 cfm. That’s a number better than many successful race heads equipped with exhaust valves 0.200 inches bigger!

This shot shows the heavily sculpted area around the exhaust port to minimize overall weight. Note the steel insert on the head bolt hole for load distribution.

To be of any use all this flow capability needs to be translated into horsepower. The question is what might we expect from a set of heads you know are going to be about the opposite end to ‘budget’ in terms of cost? Fortunately I have a simple formula that consistently produces figures for what can be expected from a set of heads on a normally aspirated, roller cammed, pushrod V8. It also has to be said that these estimated figures are usually exceeded by a good margin after a little development work has been done. To establish the potential of a set of heads based on the intake airflow a few other factors have to be taken into account. First the flow figures used must be part of a curve that has good flow through out the lift envelope. The UPM billet heads have that. Also the port velocity must be reasonable to good as must the swirl. The UPM heads also score well in these departments. This leaves the simple formula that I am about to use as a very reliable (but typically conservative) power predictor. The formula goes like this. Take the intake flow at the valve lift to be used and multiply it by 2.2. In the case of the UPM billet heads this is 460 x 2.2 which equals 1012 hp.

With the ability to flow 290 cfm plus this port can dump copious quantities of exhaust making it good for Turbo and nitrous applications. The round configuration at the header face also simplifies header production.

That number just developed can be viewed as the minimum potential that can be expected from the heads but there are a few side issues that need to be considered. The power an engine produces is a function of rpm and displacement. From a given set of heads choosing to small a displacement means the rpm required to make the hp outpaces the valve train’s capability. Too large a displacement might mean the engines bottom end looses too much in piston friction and the like. This means choosing a displacement that is likely to best compliment the head and the technology currently available in the valve train department. This being the case I’d have to guess that though these heads are likely to outpace any currently available heads on any displacement the best range to use them on would be between about 380 to 425 inches. This seems to hold good as Don has a customer that, with a 400 inch short block made 1070 hp more or less first time around. As of now the billet head looks set for a great career in dirt late model where torque is king. With 430 inches and a relatively modest cam of 260 degrees (@ 0.050) and a shade over 0.700 net lift engines have made about 870 hp and 705 lbs-ft of torque. In terms of torque per cubic inch that is closely approaching Pro Stock territory! As for turbo motors the output looks like creating a lot of chassis problems as numbers in the 2500 hp plus range are being banded around.

Here are the results of the GFN flow tests on a freshly calibrated bench. The high end numbers are impressive but those achieved on the way up are equally impressive but generally less talked about.

Since this is a billet head the end result can be far more universal as far as applications go. Any small block Ford from 289 to 480 inches can be accommodated. There are four port sizes to cover this displacement range and chambers, which start at 53 cc, can be cut down to the mid 30’s by milling.

At $6800 a pair these heads are ready to take the customers valves and associated hardware. Sure these heads are not cheap but if winning races is your goal then sooner or later you will need to up the anti. As a racer my best advice here is do it before the guy you have to race against does.

For more details go to UltraProMachining

David Vizard

[NickLosito]

You can contact Ultra Pro Machining at 704-392-9955.

Don Losito's email is Don@ultrapromachining.com

[rookie]

I have a question, I have always run small blocks and all I’ve heard is, that head is to big, this head is to big, you can’t run that big of a head on a small block, (I never listened) But now it seems every thing coming out is big, the Ls1 is 235cc, Ls7 is 250cc, the old Busch 9.5-1 compression heads where 250cc. so it’s not based entirely on cubic inch RPM or compression. Based on the valve size and airflow of this head it is at least 250cc. I’m curious is it do to valve angle or runner design that is allowing the bigger heads to be more versatile now days? When is big to big?