Today’s levels of boost, cubes, nitrous and compression are stretching the conventional head castings to the limit. The time has come for billet heads.
Building cylinder heads from casting is a mixed blessing. On the positive side, making cylinder heads from castings allows a near net form to be had before machining so there is less metal to remove. Also a casting allows the manufacturer to make a head with a water jacket. Although casting patterns can be expensive, once they are made a lot of head castings can be produced at very cost effective price. The down side of castings is that the patterns are expensive, the cast material is not as strong as its wrought billet counterpart by a big margin and once you have a casting you are stuck with porting parameters dictated by the water jacket and the existing port shape/positions.
All this was apparent to Don Losito, the boss at Ultra Pro Machining. Don was the motivating force behind the design and development of the highly successful D3 NASCAR Ford head. From Ford produced castings Don machined and supplied all the front running NASCAR Fords but casting were always a problem. As a result Don spent the best part of 6 months prototyping a water-jacketed billet head.
Making a water-jacketed billet head is far from simple. In this instance a very comprehensive water-jacketing was achieved by a method apparently pioneered by Ultra Pro. Once the water jacket is done all the other surfaces that require to be machined are accessible. The result is the head you see in our lead shot.
Although cost is hardly one of them, the advantages of a billet head are many. Firstly 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. Also the head is stronger due to using billet material to the extent that it is in another league altogether. This makes it ideal for highly boosted engines or those with super high compression or heavy nitrous loads.