One of the most common questions asked here is: “How do I get the most value for my performance dollar?” Let’s face it; most of you have a budget that will dictate careful planning for your engine project. If budget were of no concern, then the focus would become component selection most suited to the application. Although it is relevant to some degree here, I’ll address that specific method of planning in an upcoming article.
Make a Plan
As I always try to emphasize, the best place to start planning for your engine build is to set a performance goal that is realistic based on your budget. The power you hope to make is based on compression ratio, cylinder head flow, valve timing events, and RPMs. As power numbers and RPMs go up, you should plan to increase your budget in order to step up the quality of components required to add durability to the rotating assembly and valve train.
It’s my opinion that the amount of money you invest in cylinder heads has more direct effect on performance than any other component that you will purchase. I’ll also make the statement that the camshaft has at least the same effect on power output, but for the most part, the cost of the cam will be similar regardless of grind specifications. Cylinder heads, on the other hand, have a price range from less than $1000 to well in excess of $10,000. Without going into great detail, I’d like to list a few options and the approximate value of each.
Most factory castings can be ported with some degree of power gain, but typically late model aluminum castings such as GM’s LS1 yield the best results. There are quite a variety of companies out there with CNC programs available for most late model engine applications that can net gains of around 75 hp for $1500. That’s a great value in power per dollar spent.
Aftermarket cylinder heads have become more affordable and have a higher casting quality as engineering and manufacturing processes mature. Pricing is similar to CNC porting the stock castings, but the out of the box flow numbers fall short of the CNC’d factory castings. They will, however, provide substantial gains for applications where the factory castings just can’t be ported with satisfactory results. In that scenario, these would be the best power per dollar value.
Aftermarket castings do have thicker decks for a more stable head gasket retention surface, and provide strategically placed additional material that allow more advanced porting techniques. CNC ported aftermarket castings will provide the ultimate power gains, but at a cost that can be prohibitive to some budgets. Power gains well in excess of 100 hp should be expected at an average price between $2500 and $3500 for a complete set of ported aftermarket heads. Professional level cylinder heads will put you in the $5000-$10,000+ price range, and aren’t what I’d consider relevant to a discussion about budgetary prioritization.
As important as cylinder heads are in the engine system, their potential can only be realized through the use of a well-designed camshaft. As I previously stated, the real value in a camshaft is to select the correct lobes and time the events properly. For the most part, a well-designed cam will cost the same as a poorly designed cam if both are on the same type of core. In order to link monetary value to your specific application, we’ll need to look at the various types of cam cores.
Flat tappet cams have long been the standard of the OEM manufacturers, and are reasonably priced in the aftermarket. For the reason of cost alone they are a good value, but they require a special break-in procedure, and are subject to frictional losses. Flat tappets are also paired for life with the lobe they were broken-in on.
Hydraulic roller cams are in most modern engines and are an exceptional value if the engine you’re building was originally equipped with one. The cost of the cam alone is about double of the flat tappet, as are the lifters. Because of the roller wheel design, the lifters aren’t worn in to any specific lobe, and can therefore be re-used on a variety of cams as long as they are in good condition. The re-usability along with the increased efficiency of the reduced friction makes the hydraulic roller a very good value for the right application.
For unlimited racing applications, solid roller cams will make the most power. The roller wheel and solid body allow for the ultimate in aggressive lobe designs, while the billet core material provides the durability to withstand the high spring rates required to take advantage of these lobes. This style of camshaft system is prohibitively expensive to some, when you consider the cost of all the required valve train components to move up to this level of performance. The value in this style of camshaft is your ability to make maximum power with a high degree of durability.
The Other Components
While all of the components of your engine build deserve careful consideration, when it comes down to power per dollar, the heads and cam are where you need to do your research. The rest of the parts will address cubic inches and durability. Budgetary constraints drive compromise – buy the best parts that your budget will allow.
As a proponent of building your engine as a well thought out system, I’m in the process of putting together a form page that will list all necessary components and machining operations required to build your next high performance engine. You’ll be able to put in the dollar values that you’ve come up with from your personal research, and determine if you are within your budget. I’ll update this article when the form is available for you to use.
As always, I look forward to your feedback, questions, or comments on current or future topics. You can comment directly to this or any other article on the site or send me an e-mail. Please invite your friends to join us, and thanks for visiting …..