I’m pretty excited about the pistons I’m using.  I came across them totally by accident at a time when I was looking into either building a stroker motor or keeping the stock stroke.  At the time I was also interested in maximizing rod ratio.  The pistons were on Deal of the Day section of the Flyin’ Miata website.  I actually called FM and spoke to Jeremy about them months ago.  Since then, the pistons had been taken off of their site, so I considered them sold.

Fast forward to a couple of weeks ago, shortly after my engine toasted.  My car was at Apex Automotive Engineering and I was talking to Les about a plan.  Les had a ’99 head that he had Dana @ Import Machine prepare a few years back, and offered to sell it to me.  I agreed to buy the head and then mentioned the pistons I saw on the FM site.  Les suggested I call and ask if the pistons were still available.  I did, and they were.

I am told that these pistons were one-offs for a test that never happened.  The pistons are “stroker” pistons designed to work with FM’s stroker rods but a stock crank.  The result is a bump in rod ratio, which favors high revving engines.

Between the ready-made head from Import Machine and FM pistons & rods, I figured I would add the ATI harmonic balancer and call it a day.

As it turns out, I have probably read about these pistons before, and you may have too.  I was paging through Keith Tanner’s Targa Miata build a few days ago and saw a post where he installed a set of pistons that ended up standing 2mm proud of the block.  Bingo!  These must be them.

Pistons are 85mm, 11.5:1, and allow for an additional 6mm of rod length.

Pictures are here.