modeling blocks and the power of one
The icengineworksTM exhaust header modeling blocks are precision molded in tough ABS plastic to accurately represent actual straight and bent metal tubing sections in a range of popular ODs and bends. Their exact length is always 1 inch: the straight blocks are 1.000", and the curved ones are also 1.000" in total arc length at the centerline. This feature allows the design and layout of exhaust header primaries of a given length by just counting blocks in an assembly. The power to create genuine equal-length header designs goes without saying.

interlocking connectors
The icengineworksTM exhaust header modeling blocks design power comes from its main feature: a male/female connector, standard among all sizes,  that allows the quick and simple construction of long assemblies of blocks that serve as models of how the actual header primary runner will look. Designing stepped headers becomes a matter of simply combining different OD-size modeling blocks. 

of straights and curves
For each OD size, the icengineworksTM modeling blocks are offered in four basic shapes: a straight 1-inch section and three different curved ones, tight-, medium-, and ample-CLR (Center Line Radius) bends. Some selected OD sizes will have 5 different shapes: one straight section and four curved ones (please see the projected icengineworksTM modeling blocks table size on the full program release page). These simple elements are all it takes to address most of the design challenges to be encountered.

witness lines tell the story
Index marks on each icengineworksTM modeling block, when aligned in strings of consecutive blocks, tell the user that such section can be sourced from the same pre-bent metal tubing section. This feature helps manage and optimize the total number of metal sections required per runner, their location along the pipe and even the weld work associated with it. It also lets the user know precisely how much metal is needed for fabrication, down to the very inch.
forgiving precision
The icengineworksTM modeling blocks are proudly made in the USA and injected in tough, recyclable ABS plastic to be used, reused and abused if necessary. Replacement or add-on sets of modeling blocks will be available.
size does matter
The tentative icengineworksTM modeling block systems program includes the most popular outside tubing diameters used in most forms of automotive and motorcycle applications. Nine different diameter sizes are projected, from 1.500" OD (38.1mm) up to 2.500" OD (63.5mm) in 0.125" increments. Each one in at least 3 different CLR bends plus a straight block. Introduction is scheduled throughout 2006. The first OD size to be released is the 1625Series, or 1.625". Find out the CLR bends available per OD size in the full program release page.
what you see is what you get
Cleverly designed anchoring block adapters that fit through the female connector of the icengineworksTM modeling blocks, allow them to easily and firmly anchor to your engine's existing round metal starter tubes to begin the layout of a primary runner. Engineered to hide from sight, these adapters make it possible to lay out faithful 3D header models of your design without external support. And because the icengineworksTM modeling blocks represent actual metal tubing sections, they are also fully compatible with your existing metal header components such as collectors, transitions, etc. when they are firmly propped up.
mock up full-scale stepped headers
One of the icengineworksTM modeling blocks' most powerful features is the common connector system among all series (OD sizes). This simple idea allows the user to faithfully create full-scale exhaust header mockups of stepped designs no matter how extreme the step is, or how many steps the runner will have. There are no limitations, just mix the series modeling blocks of your choice.
optimize your design freely
Optimize your exhaust header design model for performance, production feasibility, costing, manufacture planning, even to verify packaging inside the engine bay. When you build your header design block by block, inch by inch, you develop a deep sense of its dimensions, volume, degrees of freedom, etc. Studying it carefully after it is finished will quickly allow you to see places where improvements can be made, such as rerouting a primary runner section differently, or maybe attempting to minimize the number of joints on any given tube, or perhaps identifying and eliminating a tough, hard-to-reach weld spot. The ability of the
icengineworksTM exhaust header modeling blocks to be quickly rearranged and reassembled in an infinite number of combinations for as many times as you want, will prove to be priceless when you want to evaluate the most optimized design possible. And all this before actually building it in metal. This is true design power!

all the information needed
When you complete your 3D model using the
icengineworksTM modeling blocks, you have at your finger tips all the information necessary to build it in metal. You will know exactly how many inches of straight and bent metal tubing are required, the number of J-, or U-bend sections and their exact CLR, and how many joints or metal sections need to be welded together. If you are interested in preserving your exhaust header model, you can glue it with commercial plastic glue or even spray paint it and turn it into your master for future reference, customer design reviews, marketing or for other manufacturing/production purposes.

adapt your existing bending capabilities to your design
If you have access to automated tube bending machines, you can incorporate your machines' specifications or limitations into your design model such as the critical minimum-length-between-bends dimension. For example, if your bender has to have a minimum of 3 inches of straight tubing between bends for grip, you can build your model making sure that at least there are always 3 straight
icengineworksTM modeling blocks between each bend. Or maybe you want to attempt to make all your primaries off of a single tubing section. The modeling blocks will help you determine if it is possible.
expand your modeling capabilities with add-on kits
As you begin to design with the
icengineworksTM modeling blocks, you will begin to see new possibilities that were not evident before. These ideas may require additional blocks but not as many to justify the purchase of a new complete engine kit. Our Add-on modeling block sets will help you complete those new design variations that will lead to superior exhaust header systems. Maybe you want to begin researching a one- or two-stage stepped design, or want to graduate your original V8 modeling block engine kit into a V12 set, or simply you want to replace a few worn out or lost units. Whatever the reason you have to use them in more than one way, they are available in many combinations. Each Series page includes its Add-On sets.
  upload your design information into your existing CAD software for further FE optimization and analysis
If you count yourself among the lucky few with CAD capabilities to design your exhaust headers, the icengineworksTM modeling blocks can still prove to be a priceless tool. You can quickly and inexpensively design several feasible designs with the modeling blocks, and then transfer the information to your CAD software of the best one by virtually creating onscreen 1-inch segments just like the ones you have in your hands. This possibility can prove to be very powerful to evaluate the best design through further computer analysis, such as FE routines checking for flow, thermal stress, heat transfer, etc.
fabrication tools to make life easier
During the development process of our own line of exhaust headers, which eventually led to the conception of the icengineworksTM modeling blocks, we have developed other tools that help you fabricate your design modeled in blocks, into a precise metal version. As explained in the How the system works section, U-, or J-bends and straight sections are all that is required to build precision exhaust headers. When working with tubing shaped in these forms, the cutting and sectioning tasks can be drastically simplified by utilizing our pivoting band saw table attachment and the CLR-specific DELRINŽ plastic Tube-Cutting Spacers. Check them out at the Header fabrication tools page.