History of Don Jensen's "HEADHUNTER" TWIN ( originally a First Ten Twin ) as told to TwoToGo by Don Jensen.
Doing all the design and work myself, I started the twin engine in October 1955.
The frame all made of .125 wall 2/1/2" seamless tubing. All bends done with heat and tubing packed with sand.Whole frame gas welded. WB 136", weight with 2 Cads. 1820 lbs.
I had 3 goals: #1 E Lakester Record - Bonneville 200 MPH club
It's first incarnation,it used the Bustle Bomb layout, but with a LaSalle gear box and quick-change with lower shaft out back to the rear engine, and a swing axle rear end. Now at this time I had just turned 21 and making $1.25 per hour. I ran out of money. So jumping to Goal #3, I made a 2 pinion rear end, took out the gear box, turned the back motor around and used 2 clutches.
I had one good 49 Cad making about 300 HP on gas, but I could not build another, so teamed up with George Wulf who had a 390" Cad. One problem, George only wanted to run Alky.
I borrowed the only thing I could, 4 nitro Strombergs. But even jetting down, they would load and flood my motor as soon as the clutch locked up. I think we ran about 4 meets - about 9 runs. 133 mph the first and 143 mph the last, car handled well, but never with a clean run.
I spent the next 5 months building 2 gas engines, 364 cubic inches, 56 heads with big valves, 305* Howard Cams, and a good 370 hp. each on pump gas. Fritz Voit had the gas record at 141 mph. Then when I controlled things, I got drafted! My last hope, one meet at Kingdon- February 1957. I made 9 runs, a test run at 142 mph, then 7 runs over 150 mph. Best run 155mph with a 10.08 ET. The clutches gave up on the last run. Car drove great.
I got back to California mid-summer 1958, took 60 lbs. off the car, installed twin disk Crower-Schiefer clutches. Went to Kingdom, rained; to Vaca Valley, called off, wind; back to Kingdom. First run broke both axles on the unlocked rear-end, tried narrower slicks, big mistake. Casing failed about 140 mph, rolled about 5 times. Both engines bounced like basketballs down the track. No injuries, but chipped a tooth.
The car was amazingly straight in front of the rear axle. But loosing 18 months work and earnings, looking at my 2 new engines, the mounts ripped from the blocks, carbs and manifolds broken, Vertex magnetos bent, pans and valve covers smashed: I quit, sold the frame to Tom & John Walsh, who ran it with one Chrys. for several years.
I still believe this car had more potential. My next step was to be lighter clutch springs for more slippage, and I had started building a super rear axle. Using 2" 4130 bar, casting my own hubs with Buick aluminum brakes ( I finished this and used it in the last slingshot I built ). Last step - superchargers.
This car had traction all over the front engine twins and could have been competitive for several more years.
TwoToGo not only wants to thank Don Jensen for his Twins history, Don also contributed another "First Ten"
Twin - the Emmett Cull Twin, plus several photos.
#2 Worlds standing Kilo record
#3 150 MPH on gas 1/4 mile