Some Factory 340-4 and 340-6 Dyno Runs

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VOETOM

VOETOM

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I have had these for a long time and found them while doing some transmission data searching for another project I am on. I knew many would love to see the true output of the 1971 340 four barrel and 1970 340 six pack engines. Note these are runs after "carbon cleaning" and with and without full exhaust. Lots of notes and numbers so look closely.

With some magnification, I believe this shows that the three two barrel engine made 350 HP at 5800 rpm and 390 lb. ft. of torque at 5000 rpm with dyno room exhaust, air cleaner base plate only, no intake manifold heat, and a lab oil pan.

70 340 6 4.jpg
 
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Another run

With some magnification, I believe this shows that the three-two barrel engine made 290 HP at 4800 - 5200 rpm and 340 lb. ft. of torque at 4000 rpm with full TA exhaust, air cleaner, fan, intake manifold heat, and factory oil pan with windage tray and normal spark advance.

70 340 6 11.jpg
 
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71 340 4 Run

With some magnification, I believe this shows that the Thermoquad 340 engine made 280 HP at 5400 rpm and 380 lb. ft. of torque at 5400 rpm and I bet a dyno room exhaust, air cleaner base plate only.

71 340 4 2.jpg
 
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71 340 4 another run

With some magnification, I believe this shows that the Thermoquad 340 engine made 320 HP at 5600 rpm and 360 lb. ft. of torque at 4000 rpm with (I imagine) dyno room exhaust, air cleaner, and everything set for max power.
71 340 4 5.jpg
 
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71 340 4 last run. I am really sorry that I do not have these for a 68 manual 340 or a 69 340 automatic.

With some magnification, I believe this shows that the 1971 Thermoquad 340 engine made 287 HP at 5200 rpm and 345 lb. ft. of torque at 3800 rpm with full exhaust, long factory tailpipes, stock fan with clutch, full air cleaner.
71 340 4 9 .jpg
 
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wicked cool, where did U get this stuff? and very difficult to read. please summarize the data. thank you. I think the 71 340 4 made 290, and the 70 340 6 made 290?
 
Like you all note, a couple are tough for me to read as well but I'll use my iPad and blow them up and get some numbers off later. I can't recall who shared them with me but it has been a long time ago.

My comments after reading them closer are as follows: Note how powerful the 340 really was with full exhaust, both the six pack and four barrel. And note they used the squished and mashed left side 2" outlet pipe? This one pipe alone kills about 6 to 10 hp at the track with a stock cam at normal shifting rpm (on my car). Now, note the big increase in power with it all optimized? You can see that Chrysler rated the 340 with it all together as it would be in a car whereas others rated their engines optimized. This is one reason 1968, 1969 340 Darts and Barracudas were so relatively quick compared to other 275 hp small blocks in similar sized cars. I never found another similarly-rated engine (Ford or Chevy or Pontiac) that ran as fast or as quick, stock, as my or my Dad's or my pal Mark's 340 did. And, it is easy to see why opening up the exhaust, removing the air cleaner, adding cold air, optimizing the spark, and running clutch fans made these engines so powerful. They truly were.

Sorry if you all read different values than I interpreted. Even with the iPad, the six barrel ones are tough to correctly get.
Tom
 
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'Note how powerful the 340 really was with full exhaust, both the six pack and four barrel.'

So it seems to me, that for stock engines tne Thermoquad was a perfect replacement for the 6bbl configuration of 1970.
 
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