Welcome to Inertia Motorsports, where you can get #inertiapowered ! 

Home of the Spartan and the SRT MAX Plus camshafts, record breaking Hemi builds and much more! We have built more than 450 HEMI strokers from oilpan to intake over the last 10+ years. Nobody else in the business has as much experience as we do with this motor platform.

Our goal is to provide the Mopar community with top of the line parts with the best customer service in the industry.

The two vehicles at the top of this page are a Charger SRT8 and a Ram SLT owned by our great customer Collin Ebalo. Collin has entrusted us with the heads/cam combo on both his HEMIs and we're very pleased to be part of his builds. Thanks Collin!

We are here to serve you, so please give us a call or send us an email (or contact us via Facebook, Instagram or Twitter) and we are more than happy to help with anything we can.

Why run Inertia CNC ported heads? What sets us apart?

Over the years while speaking with customers I’ve discovered that there is a lot of confusion about ported heads.  For example, many of the people who inquire about heads ask about ported and polished heads.  In general, “polishing” is a term from the 50’s and 60’s where they would polish the runners to make them smoother with the idea of increasing air flow. In reality this isn’t the case. Due to boundary layer effects, a smooth surface doesn’t actually flow more air than a rough “as cast” surface and in a wet flow application, the smooth surface can actually allow fuel to puddle and fall out of suspension.   Therefore, polishing is often just a way to justify charging more money because it looks as if more work has been done because it’s shiny and cool looking. In most cases a shiny port doesn’t hurt anything unless it’s wet flow like an intake port or wet flow intake manifold in which case fuel can puddle causing fuel distribution problems. Due to shearing, a rough surface can help keep the fuel in suspension better.

Another misconception is the flow bench. I used to be guilty of this one when I pretty much assumed that the more air a port could flow on a bench the more potential for power it had. While it’s true that flow numbers are a decent tuning tool, they aren’t as significant as most people (including many porters and engine builders believe). There are things you can do to a port that will substantially increase flow numbers and will kill power and there are things you can do that kill flow bench numbers and will pick power up. Flow bench numbers in a static valve condition are just a minor tuning aid for cylinder head development. That, and many shops are going to advertise the biggest numbers regardless of what they actually see. A good example of this is our stock valve 6.1 head made 368 CFM on a bench and a competitor’s head was being advertised at 355 cfm. A month later the same competitor was advertising 372 cfm. The real give away here was there head now made a bigger airflow gains from 0.550” lift to 0.600 where the 372 rating came than it did from 0.500” to 0.550” lift and that is extremely unlikely to happen, to put it kindly. Furthermore, flow benches are similar to dynos in that you can see quite varied results from one to the next. Our heads that made 368 on a dyno in Houston only made 345 on our porter Phil’s bench.

Making power in heads is primarily about shape and size and it takes a lot of knowledge and experience to find out what those shapes are and what the correct size is for a given application. The new Hemi already has a pretty good port and valve job so it’s not like the good old days where almost anything you did to increase the size of a small block head would pick up power and most machine shops and porting services could get some decent results. To make decent power gains on a new Hemi you have to know what you’re doing. In this case to get our heads done I went to one of the top race head shops in the business that does top level work at the highest levels of racing. Inertia’s heads are done exclusively by Phil Coleman who owns Finish First Racing Heads. I hooked up with Phil about 13 years ago because I found out he was doing many of the W8, W9 and P5 NASCAR heads on the Dodge Cup cars and Trucks.   It turned out he was doing a lot of NHRA Pro Stock work also,as at that point his heads were on over 200 NASCAR Cup car event wins and 4 National Championship Cars, as well over 200 Pro Stock wins and 4 Pro Stock Championships. Recently I found out that the 68 Hemi super stock car that won last year’s superstock Hemi shootout was running his heads. So Phil knows Hemi. Not many if any other head porters have that kind of resume.

What this translates to for our Hemi heads is we get about as much out of our heads as the casting allows. Furthermore, with the work being done by a “Cup Shop” it’s being done on equipment the typical race head shop doesn’t have. For example our valve jobs are performed on an $80,000 Newen EPOC single point CNC valve job machine that allows the valve job to be laid out on a computer screen and then duplicated by theCNC cutter It can do things you simply can’t do with pre shaped cutters that only offer ½” in order to fit the entire valve job. That’s why most of the better shops doing porting on Hemi heads use a 5 angle valve job on the intake side. The Newen allows for a 6 angle job that blended into the port better. Then the exhaust side is a radius job since you don’t need the edges of the seat for fuel shear on the exhaust side.

This level of shop also has the capacity of normally being able to turn a set of heads around in a week or sometimes less if we don’t already have them finished and bagged on the shelf. That’s because they have 3 Haas CNC machines to do the work very efficiently.    

In the end a CNC machine can only duplicate what the head porter has done and that’s where having a porter with the experience and ability to get the most out of a particular casting come in to play.

If you’re considering a set of heads for your 5.7, 6.1, 5.7 VVT, 6.4 or 6.2 HEMI, keep us in mind and give us a call for a chat about your needs and wants for your vehicle.

- Stu Hansen

Inertia Motorsports


Thank you for visiting and we look forward to helping you make your car or truck the best it can be.

Email us: info@inertiamotorsports.com




Service & Sales:




    1 - 12 of 47 items
    Sort By: