Use the 360. Cheaper, easier to build. Roller motor, etc, etc,. A 360 can make just as much horse power as a 340. The new 10:1 coated pistons/rings are super cheap. Stroker kits available everywhere for more cubes.

Sell the 340 or keep it for a true 340-Car.

If his Demon is basically a clone, then thats another reason to build the 360.

In my opinion, the 340 has too much value to be in a clone car.

do the 360...cheaper and more performance.

you can not compare stock engines from 40 yrs ago, with two engines being totally rebuilt today..

Mopar Action got 425 HP out of a 360/380 crate motor. When you rebuild it, you might think about sticking very close to what a crate motor spec. is....maybe add a bit more cam.

You tell me. My 95 Dak sport w/ a 5.2 5 speed does 14.08 w/ zippy internal mods using the stock intake. All it had was short headers, MP computer amd a 3" single exhaust. My 72 Swinger was a 10.5:1 340, w/ ported J-heads 340 cam, 1.6 rollers, RPM air-gap TTi headsers w/ 3 inch X-pipe and a holley 750HP went 13.82. With the 625 Carter 14.teens.
So I'd say stock 340 and a Stock 95 360 in the same car 360 wins.

If he already has a 340 I wouldn't bother with the 360.

We bought a running 360 with trans for $99 and treated it as a core.

As Ive said before, there is NOTHING magical about a 340. If the 340 and 360 are built equally....I'll take a 360 any day of the week

The 73 340 with higher compression than the 74 360 made LESS HP than the 74 360 even though both motors had the same heads, same intake, same cam and same carb. They were rated the same way those 2 years and were both offered in the same cars. The 360 made 5 more hp and 30LBS more tq. I beleive 74 was also the same year the 360 got cats so there is another hit on the 360 and it still made more power. That is about as close a comparison as you can get and any one who has driven a stock 73 340 car and a stock 74 360 car knows the 360 would eat it's luinch any day of the week. All things being equal the 360 will whoop the 340.

The 340 simply got a good reputation back in the day and it always will because they were bad little motors but you also got to remember the 360 was never offered in a car as light as a 68 cuda or dart.

If you took an e-58 360 and gave it 10.5 compression pistons and the same good flowing 68 340 ex manifolds it would make quite a bit more HP than a 68 340. It is just plane a matter of physics and good common sense, and we all know .040 bore will not make near the differance as .27 stroke increase, that "biger bore" only gives you .020 more clearance from the valve to the cylinder. People who think equally built 340s are faster than an equally built 360 are totally smokeing crack or something unless you are talking bone stock motors and even then there are short-comeings of the 340. Even in stroker motors you are only talking 8 whoppin inches for a block that will cost you about $600 more.

340s rule 360's drool....

340 vs 360 -

The 360 has a better rod to stroke ratio than the 340 for building HP, and it will deliver a higher piston speed at lower revs than a 340 which also helps(and the 360 has this over not only the 340, but also the 273 and 318) .

Why is it better? - Given the formula for power = revs x torque divided by 5252, and that torque is the result of an explosion on top of the piston pushing down on the rod which pushes against the stroke(longer stroke = longer lever) it would appear that a factory stroke of 3.58in versus 3.31 will result in a greater amount of torque at all revs.

Thus - this equals more average torque, which equals more average horse power..across the rev range.

So again it would seem that given the same heads cam and intake that the 340 is "owned" by the better designed 360.

In its favour the 340 has bore, but we're not talking much, its like 40 thou ...........which given the area increase it offers its still not enough to offset the gains of the extra stroke of the 360.

So it appears the 340 isnt as good as a 360, But wait theres more!!

- The ability of the 360 to generate greater torque everywhere is the reason its a better motor for street cars and drag cars if the required rpm is less than 7500 -

(and no, torque is not reserved for low down and hp for high up, one is a measure of a direct quantity, one is a derived number from a formula - although with money more is possible but 7500 stays in the realm of factory cranks and rods)..

...... thats not to say that a 340 can't go hard, its just that a 360 can go(and does) go harder when fitted with the same heads cam and intake.

As for the weight , the 360 pistons on average depending on brand are typically lighter than 340 pistons(due to bore size, but the extra comression height is typicaly the main reason) .

If you weigh both blocks you get about the same number(give or take for corrosion and casting, and we are talking factory, not race blocks), yes the 360 crank is heavier, but the extra mass we're mainly concerned with is along the crank center line so it is a minimal.

So lets look at the old argument - "but 340s love to rev"

In reality, what we are seeing is the function of the rod/stroke ratio for a 340 - the engine MUST rev harder to achieve the same HP as the 360, thus both engines are the logical end product of functional design - the 340 was built to make its HP at high revs becuase thats what the engineers knew it would have to do with its rod/stroke and bore. Thus the forged crank and large valve heads.

The 360 is a torque monster by virtue of its capacity and stroke - but its rod/stroke makes this torque right through the range - and ends up making more power for the same revolutions as a 340.

So the more oversqre 340 shows all the characteristics one would expect - it spins up quickly and appears to make power at higher revs -

Trouble is, its making less power than the 360 below this "magical point" - and you're losing the race in the process! LOL!!

Lastly , the more oversquare design of the 340 enhances its durability at high revs, but as we've discussed, we're talking street engines so this advantage is negligible at 6500 rpm.

--------Anyhoo, back to your question - No substitute for cubes, so the 360 over the 340 will always be a more practical option for street duty.....Torque rules in the street.


If you don't own either - buy a 360.