FAQ For Twin Cam Cylinder Head

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This is not now nor will never be an open box, install head affair. The head casting is just the staring point for a competent engine builder to put their “mark” on the head. I feel this is the best way forward so that you are not tied into purchasing parts that are not appropriate for your build. The prices I’m throwing out there are based on what I believe the production heads will take to machine as well as estimates on having the additional automotive specific machining done. As more heads are produced more accurate estimates will be made.

I’m constantly updating this list.

1)What’s the price and when can I buy one?


The head will come without valve seats and valve guides. The best thing to do if you are truly interested in a head is to start a dialog with whomever will be building the head and work outward from there.

As of September 2018 I have done the first production run of 4 heads. Two have been sold and at this point I’m holding off on selling any others until SN001 (mine), SN003 and SN005 are running. Mine is 2-3 weeks out.

2) Will it have VCT and variable valve lift?    It won’t have variable valve lift but it will have the ability to have Variable Cam Timing on the intake only. I have worked out all of the mechanical issues to implement it and every head and cam tower set will be able to utilize it.  If you opt not to go for VCT when you purchase and you want it later on you would need to purchase new cams and have some modifications done to the towers.

3) What alloy is the head.  The head casting is A356 aluminum. After casting it is shipped to a company that does Hot Isostatic Pressing. They heat the head in a pressure vessel to around 900 degrees F and then pressurize it in the 20,000 psi range. This compresses the microporosity in the casting and makes the density close to billet. It is then shipped back to the foundry where they are heat treated to a T6 condition.  After I machine the head castings they are shipped to have them vacuum resin impregnated. This seals up any remaining porosity. At this point the resin impregnation is more of an insurance policy.

4) What will it flow? I had the prototype Flow Tested     This is with minimal porting done. Here are the flow test results on V2 after Rebello did some port work on it. Rebello figures that the ports can easily support 450 HP normally aspirated.

5) Any provisions for coil on plug ignition scenario?  Yes. The valve cover has bosses on the inside so you can point the wires towards the front or towards the rear.

6) What are you planning for intake and exhaust manifolds?  I’m casting a single 2 barrel manifold and that will be used 3 times. The inner ports are formed with 3D printed sand so people will be able to specify what they want for an additional cost. Other designs will develop over time I’m sure. For my build Xnke from HybridZ is building me a custom header. I imagine others will want to use him but I’m not planning on stocking or selling exhaust.

7) How much horsepower is it putting out? Not sure. Making power wasn’t the purpose of the V1 prototype. It was about testing the valve train and trying out different timing chain configurations. If ultimately power is what you are looking for then the head needs engine displacement to make power. I would think 3.1L minimum. A 3.5L build is projected to put out 450hp at the crank.

8) Why didn’t you use the Honda timing chain?  The crank gear was too small to fit over the snout. single chain was my preferred route but there was just no way to make it happen. At least not with off the shelf components.