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Heads are basically the same except valve size and that can be changed.

The 360 is cheaper to buy and has more cubic inches unless you are strokeing it. Equally built the 360 will make more TQ and dare I say... HP

If you are building an A-Body from about 68-71 the 340 tends to add value to a car more so than a 340 because the 340 was the factory performance engine in those cars.

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360 = best bang for the buck.

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& there are much better cost effective performance cyl head options available than the old 70's open chambered 340/360 heads

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Generally when you have several engines of the same basic design the smallest will make the most power per cube given equal levels of preparation. While this can be an important factor in class racing, when it comes to the street or brackets size matters and big is good. The 360 has several advantages over the 340. 1st. 20 more cubes. 2nd. The bigger mains which are often criticized provide more crank pin overlap which helps even more when using a stroker. IMO most of these engines will never turn enough rpm for the increased bearing speed to become a factor. 3rd. Since all the LA engines share the same deck height and rod length the 360 has a lighter piston than the 340 which is probably at least as important to revabilty as the 340s shorter stroke. 4th. A 4.030 bore size [ a common 360 overbore ] is probably one of the cheapest and commonest ring sizes available. Lastly, cost and availability is much better with the 360. 340s are great for image and restoration, 360s are for making cheap power.

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I like the 340's as good as anyone. A 360 is much easier to find and cheaper to obtain. You will come out ahead because of the 20 extra cubes. If you have a 340 Id sell it and get probably two 360's out of the deal. They can make crazy horsepower and torque for reasonable money. save the 340's for the resto crowds. As far as small blocks go, the 340 is a legend but I'll take power anyday

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I'd build a 360 ANY day over a 340. There is nothing magical about a 340...there never has been

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from 68-71 it was the biggest small block mopar ever made,

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I shyed away from them soley because of the cast cranks. Small blocks were made to turn upstairs and I just didn't feel safe turning a cast crank up where I could overcome the torque loss of a smallblock

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Im wondering if a 340 would be a better choice to build a moderate hp engine, I have seen 340s for five hundred with heads 360 are cheaper but will I need to buy better heads anyway and really not save any money. thanks for your advice

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Back in the day those heavy 340 pistons were stressing those steel cranks something fierce. 360 pistons were a lot lighter and easier on cranks. Because of the higher cubes the 360 did not have to rev as high to make the same power, also easier on cranks.

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Fact is a hevier piston is harder on a crank and rods than a lighter piston, any one who argues that is or or mabey

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Won't argue that point but those cast shafts will take anything a those 340's would throw at it and then some.

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Ok I see Im beating a dead horse here. One last question if a 360 engine setup is so much better that a 340, why are all the race blocks based on the 340 instead of the 360? Making that limited power improvement at low end will get far overshadowed by the ability of the 340 to continue to make power up to 8000 rpm. I did not want to start a heated discussion nor will I continue being a part of it. These are just my opinions .

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Just for kicks
since I already had the
Performance Trends Engine Analyzer 3.2b software with 1995 Magnum 360V8 factory specs,
I changed the short block to 3.31 stroke and 4.17 bore to simulate a 340 style short block, but with the same displacement. (I realize 360 blocks can't be overbored that large)

Torque went up 6 ft-lbs at 3200 rpm and
WOT Horsepower went 5 hp at 4000 rpm
with the shorter stroke and larger bore.

Willem Weertman's write up of the creation of the 360 in his book:

http://www.amazon.com/Chrysler-Engines-1...5606&sr=1-1

seems to indicate it was all about low cost, and he seemed almost apologetic about the external balancing.

I have wondered why 3.88 inches was chosen as the stroke of the V10. Weertman writes that this stroke length was ordered by Bob Lutz simply to bring the displacement to an even 8 liters.

The story in the book about how the first v10 was built by a specialty shop by brazing on 2 more cylinders to a 360 v8 was interesting.

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Ok I see Im beating a dead horse here. One last question if a 360 engine setup is so much better that a 340, why are all the race blocks based on the 340 instead of the 360? Making that limited power improvement at low end will get far overshadowed by the ability of the 340 to continue to make power up to 8000 rpm. I did not want to start a heated discussion nor will I continue being a part of it. These are just my opinions .

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No Forged 360 crank - Big deal - Mopars are not noted for crankshaft breakage. Forged or cast.
The 360 is not a high RPM oriented engine like a 340. They make it at a lower RPM.
Like I said if the 360 would have been made during the non emision ere it would have been 'the small block'. The 340 would not hold a candle to it.

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Patrick the 4bbl 360s had the same cam as the high comp 340 but no high compression and lousy exhaust flow and leaner carb settings for emmisions.

The closest you can find them in stock form for comparison is a bone stock 73 340 in an A-body with low comp lousy exhaust emmisions calibration and compare it to a 74 360 in an A-body. The 74 360 will woop the 73 340 every way imaginable.

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