Chucky - I'm not positive but I recall someone, possibly Brodak, offering a CL/stunt version of this engine a while back.

A fellow was having some sort of runaway problem with his so he sent me the head and I modified it. He claimed that it cured the issue and it became a good running stunt powerplant.

I do not know how the engine differed from yours - possibly some timing changes. Someone here will certainly chime in.

Bob Z.

Hi Guys,
The small front end and the exhaust flap tells me this engine is probably from early to mid-70's. The 40 started life as an RC sport engine so it had mild timing for easy handling for sport flyers.
K&B 40's then became a popular sport pylon engine and K&B kept ongoingly changing crank and port timing and a bigger  bypass area, head shape changes and etc., to make it a better race engine, but there was no change in model designation or outward appearance. The K&B box just said Series 70 and later Series 71 models. (I never even heard of an 8011 designation back then.) At some point, a bigger front end was created to be stronger for pylon racing users. It is just a useless extra ounce of weight for stunt use-Stan Powell upgraded the bearings in the small front end and they worked just fine. I didn't even bother to do that. My engine weighs 9.1 oz. without muffler. ( please note* the Hemi head [not squish band or wedge head] gave the best stunt run)

 The good news for you is, I ran an engine like yours dead stock and before all the racing modifications were added by K&B and it made a fine stunt engine for airplanes of up to 630 sq" & up to 55 oz.in weight. Stan Powell refined the engine and Les McDonald used it to win a world championship with his Stiletto 660.

I used a 12x5 Rev-Up prop cut to 11.5" or 11 5/8th" - This was the first time I used a higher rpm and lower pitch 2/4 engine run and I had loads of power (9,500-10,500 rpm tached on the ground).  A Rev-Up 5" pitch prop specs out on a pitch guage closer to 4" pitch on many props so you might want a 4" pitch prop.I later acquired and engine modified by Stan which was great. Fuel was all castor, 24%% oil,5-8% nitro-the oil controled the engine 2/4 break.
 I loved my K&B's.                                         Best Wishes,  Pat Robinson

I've flown the 4011 model with the larger front end in stunt a lot and really like it.  One flip starts and run the same every time.  I cured the wind up problem with change in venturi size and change of prop.  Mine turned an APC 11 x 5 at 9,700 as I would release it.  I'm a mid-level Advanced flier so do not notice things a better flier might comment on.  Mine ran better upright or inverted than they did side mounted.

Hi guys,
A fellow club member John Hagen picked on modifying K&B 40's after Stan Powell dropped out of the hobby for awhile. John did use the later model K&B's with the big front end and he was even able to run squish band heads with more head gaskets, so even those engines could work just like Stan's engines.

We all used the dykes ring cross-scavenged engines. One of the key pieces that made Stan's engines so good was the quality and the fit of the ring to the liner. Normally dykes rings engines are loose and easy to turn over, but Stan's engine had loads of compression when you turned it over by hand and it was a hoss in the air. The first thing I would do if I bought another K&B 40 is send it to Mr. Bowman for a quality fitted ring.

Brett, Stan went through and exchanged lot of parts because K&B kept changing specs for racers, until Les won at the world championships and then K&B began providing Les and Stan with parts speced out for their needs.
So, this varability of specifications may account for why the K&B didn't become widely used. In addition, even after Les won repeatedly at top level competition, many people I talked with still believed that the K&B 40 was only a high rpm "hot rod' motor that was unfit for stunt. 

Looking back, it seems that Stan's K&B's were closer to a PA or RO Jett than a stock K&B 40. The modern engines are obviously superior, but the K&B was ahead of it's time.
I have no knowledge of the ABC schnerle port K&B.  Maybe Willis Swindell could weigh in on that 40.- Pat

Thanks for all the good info.  Need to get it on the test stand and see how it runs.  Waiting on a new rolled pin for the prop driver from MECOA.  The one that it had was only partially installed and mangled up on one end.  Looked like someone tried to press too fat of a pin into it.  The prop driver configuration definitely looks weak with the large flat for the set screw and the pressed in rolled pin going through a 3/32" hole in the shaft.  These two features probably don't help the shaft strength a bit.  Guess that's why we don't see this kind of setup anymore.  When I first got it, I guessed it to be a bushed motor until research indicated it had a small front bearing.  Unusual setup.  Given the cost, I'll try to run it as takes what comes.

Thanks again.