B Series Head Update

This past week, we sampled the latest prototype heads. I'm pleased to report that the next changes we've prescribed involve relatively minor machining details on the B16 chambered head. The closed (GSR) chambered head is requiring a change in the combustion chamber/exhaust port cores to "fix" a couple voids in the latest casting.

The intake ports are finally exactly as we wanted (see picture below), and when combined with the valve seat changes we prescribed along with new chamber corner radiuses, the net flow increase has been 12cfm, placing the (as cast) intakes in the 280+cfm region.

I've also requested .002"more valve seat insert interference, a slightly smaller than stock valve guide ID of 5.485-5.490mm (for longer service life), a slight increase in cam cap height (to permit spray-bar clearance for future high lift (.550+")cams with stock base circles), recessing the spark plug .050" for more piston dome clearance with projected tip spark plugs.

Below you can see the final 81.0mm closed chamber. If you look closely at the area between the quench pad and the exhaust valve seats, you can see the small voids we're working to eliminate from future castings.

The B16 chambered head sample is currently being assembled at Endyn for testing. We should have an engine on the dyno within a week for endurance testing.

We have also received the rocker arm forgings and they meet all the specifications we've called for. The rockers are still awaiting carbide pad attachment and finish machining. I don't expect to see final rockers for another three months. I might mention that we have also decided to manufacture rockers for H22's. As many know, the factory H22 rockers are "soft"....and replacing them is expensive as hell, so we're attempting to help H22 enthusiast's with some less expensive components that are of superior quality.

We will receive sample camshafts in one week for measurement, and dyno evaluation. We already have the new long-travel LMA's, as well as the rocker shafts, and these will also be installed for our dyno testing.

Obviously, all this has taken longer than any of us expected, but I was dead set against putting a head on the market that still required some updates during production. My goal was and is to have a head that's an outstanding value right out of the box, and I believe we're just about there right now.

As of today, we expect to have finished heads with the B16 chamber ready to go around the end of May, and the GSR chambered heads will be good to go around the end of June.

We are also beginning work on a true GSR head. This head will incorporate our GSR chamber with true GSR intake port/flange layout. Expect this head to be available sometime in early fall 2008.

In addition to the H22 rocker arms, we are still working on the K series heads. I fully expect to have the heads available with two different combustion chambers (one stock-style) and the other based on our sculpted small-volume chambers utilized in our pro K and F20 heads. Porting will also be optimized beyond anything available from the factory.