Dodging the shrapnel

Dan Gurney had a penchant for wanting to win the Indy 500 with what was then called a “stock block” engine.  The time was roughly mid-1960s and his first effort focused on a small-block, fuel-injected Ford.  Interestingly, the cylinder heads were an outgrowth of a project Dan had initiated with the renowned Weslake Engineering firm in England.  In fact, he’d previously worked with Harry Weslake on powerplants in the F1 cars Dan drove on that circuit around the same time period.  The Championship Indy cars produced by Gurney’s “All American Racers” shop did exceptionally well with the Gurney-Weslake package, qualifying at the 500 as “second in class,” as Dan put it to me right after posting the second-best time to the Granatelli “Swooshmobile” turbine car in 1967. 

But the point is that Dan had a burning desire to win the 500 with an “All American” engine, or at least one based on an iteration of a stock cylinder block.

Some years later, Dan gathered up his team and drilled into working on a small-block Chevrolet engine, also destined for a show at the Brickyard.  It would be his last attempt.  This recount deals with an event along the road to configuring that engine to do battle with the “engines du jour” of the ‘80s.  Here it is.

One member of Dan’s “AAR” group was named Stump Davis.  While I’m certain the “Stump” label was fashioned due to the fact that he was a bit diminutive, it fit and was the only first name I ever knew he had.  Stump was pretty much Dan’s “go to” guy when it came to handling the details of jobs both big and small.  He was typically the guy who, if Dan wasn’t available, would call me at Edelbrock to ask about parts and such.  Likeable and reliable, you could usually find him in the midst of just about any AAR venture.  In this particular case, ad-venture. 

Indy rules then in play set the stock block displacement at around 210 cubic inches and allowed turbo-supercharging.  A somewhat over-square (larger bore than stroke) small-block intended to run reliably in the 8000-plus rpm range became the object of AAR’s research, at least initially focused upon evaluation and development on the shop’s engine dynamometer.  Stuff typical of the day.

In this particular case, the AAR engine dyno was housed in a relatively small concrete block room inside the shop.  Parts had been known to hastily exit high rpm test engines and Dan reckoned a cement block cell would be good insurance against such events.  At least that was his belief.

Maybe right here, a more detailed description of the test cell would be in order. 

It was, in fact, a concrete block “house” that not only contained the dyno itself, but also included the fuel flow meters that monitored fuel delivered to a test engine during testing.  Note that: during testing.  Since brake specific fuel consumption (bsfc) data is mathematically computed by dividing observed (not corrected) brake horsepower into fuel flow (in pounds/hour flow rate), obtaining accurate fuel flow numbers was critical to determining overall engine enrichment and, most importantly, combustion efficiency.  In the day, the procedure involved running a test engine up to a specific rpm, applying dyno load until the desired engine speed was reached (at wide-open throttle) and observed power was recorded at that speed.