After returning from WWII Navy duty in the South Pacific, Jack opened up a small repair garage in Hermosa Beach which became the official headquarters for Jack McAfee Engineering, aka "JEM ENG".  While not being much more than a few service bays in the back of a service station, it was the birth place of an idea that resulted in some serious hot rodding history; the first blown Cadillac 331 "mil". 

While working night shifts at General Motors Truck & Coach Division located at 2700 Tweedy Blvd., South Gate, CA, Jack was sent to receive factory training on their 2-stroke Detroit Diesel truck engines which incorporated Roots type blowers.  Upon completion of the training, Jack designed and built a street blower kit for the Cadillac 331 engine incorporating the GMC 4-71 size blower.  The kit included: aluminum intake manifold with cooling fins and pop-off valve, front drive shaft carrier, upper and lower pullys, throttle linkage, and upper carburetor manifold assembly.  Matched Good Year belts were also supplied.  I believe the photo below shows the first installation on a Cadillac Convertible Business Coupe:

The initial attempt shown above proved to be very effective....actually too effective for street gas. Pre detonation reared its ugly head causing McAfee to incorporate Benzene injection shown below on the reworked manifold. When I asked my father why Benzene, he said it had the highest octane rating of any readily available petroleum product (101 RON). Note the added Benzene auxiliary tank and manifold bowls:

Other carburetor configurations were developed as shown here in this down-draft set-up:

One item I need help with identifying is what type of injectors are used on the following intake set-up:

Probably the last photo taken of any installation was below showing an Allard J2X at 1952 SCCA Golden State Park race.  My dad is in the satin "Hollywood Throttlers" jacket.  Unfortunately an associate was allowed to drive the car on the street pre-race day and burnt a piston having too much fun.

Known facts:

I have very little information on the JEM BLOWER kits other than they were developed in the late 1940s. The March 13, 1950 edition of Autonews magazine shows a picture of the JEM blower kit and states "Puts out 10 pounds and very smoothly. Showed 40 percent increase in power in dynamometer tests." Factory SAE ratings for the Cadillac 331 OHV engine was 235hp.  Hence blown output would approximate 330 hp.  I have some very crude Polaroid photos showing the dyno testing in process but they are in horrible shape.

In addition to the Autonews magazine article, the 1951 February edition of Motor Trend magazine ran a two part article on super charging which included the J.E.M. blower:

Unknown facts:
Was the JEM blower kit reviewed or advertised in other publications?  I would really appreciate it if anyone with knowledge of these forced induction kits would share their information with me. Not being of that era, I don't recognize what types of carburetors were used either. Together, I hope we can unearth some more information to help today's hot-rodding community better document this project of yesteryear.    Please contact me with any information HERE