Power advantage between Ford 351, Mopar 340 and Chevy 350??

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harrisonm

harrisonm

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I was thinking (which I sometimes do) about these three similar displacement small blocks. I know they arrive at their displacements through different bores and strokes, but I would think they were somewhat similar. Here is my question. If you took each of these engines and installed cams with the same specs, used the same type of rings and bearings, installed heads with the same valve size and very similar flow characteristics, Installed the same intake (ie an Eddy Air Gap), the same carb, and basically the same headers, would the engines make pretty much the same power? I know there are lots of other factors. I am just wondering if all things were as equal as possible, would they make the same power? We like to think that our Mopar engines are the best, but I wonder which engine would come out on top?
 
If you took all 3 engines, put the same cams, carbs and manifolds on them, limited them to the same CR, used restrictor plates to ensure they had similar flow numbers, you'd have NASCAR.
 
413 said:
Depends weather a 351 Windsor or Cleveland
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Along with a 351M... Plus the 351C 2V or the 351C 4V or the Ram Air/ Boss 351

Also depends if it's a LT-1 or a Goodwrench rebuild...

And it depends if it's a 68-71 340 or a 72-73 340 with dished pistons...
 
This ain't exactly what you looking but give and Idea he has a lot other these type of vids to help answer you.



 
harrisonm said:
I was thinking (which I sometimes do) about these three similar displacement small blocks. I know they arrive at their displacements through different bores and strokes, but I would think they were somewhat similar. Here is my question. If you took each of these engines and installed cams with the same specs, used the same type of rings and bearings, installed heads with the same valve size and very similar flow characteristics, Installed the same intake (ie an Eddy Air Gap), the same carb, and basically the same headers, would the engines make pretty much the same power? I know there are lots of other factors. I am just wondering if all things were as equal as possible, would they make the same power? We like to think that our Mopar engines are the best, but I wonder which engine would come out on top?
Click to expand...

Pretty much if your talking similar aftermarket heads.
 
If you are talking on the late 60's early 70's engines with stock cast iron heads, the 351 Cleveland with 4V heads can make more power that the Mopar 340 or the Chevy 350 just because of the amount of airlfow through the heads. Same as the Mopar 340 should make more power than the double hump 350 as the heads flow a bit better. If you are talking about the 351 Windsor it would probably be at the bottom of the pile as the cast iron 351 W heads do not flow very well.

It seems that your question is more along the lines of the bore/stroke combination of the engines, rod to stroke ratios, and what difference that will make. As if everything else if basically the same, with head airflow, intakes, carb sizes, headers etc... the only real differences would be the basic architecture of the engines. The bore and stokes are very similar, Chevy 350 and Ford 351 (both C and W) have a 4 inch bore, and the 340 has a 4.04 bore, the Chevy has a 3.48 inch stroke, the Ford a 3.5 and the Mopar 340 a 3.31 (360 has 3.58). The best rod to stroke ratio would be had by the 340, but not by much, the 351 W would be right behind and the 350 Chevy and 351 C would pick up the rear. Having said that the difference is minor, so I doubt it would really make much of a difference. If these engines were built to the same specs as you suggest, they would all make really close to the same power. I would bet the whichever engine had more displacement would probably make more power and torque, so a 360 Mopar would probably make a little more power than a 350 or a 351 and certainly more than a 340. Now, if the displacements were the same, I bet the power difference would be almost nothing. After all an engine is just an air pump, if the amount of air coming in and going out of these engines is basically identical (as per the head flow, cams, carbs, and everything else being the same) they should make, at the same displacement, about the same amount of power. The differences in bore sizes and rod/stroke ratios are not enough to really make a big difference.
 
Hot Rod (I believe) did a rule limited build of each and put them in 3,400 lb cars for ET comparisons many years ago. Mopar had a 360 in a blue Duster. It ended up the fastest. I don't recall the year.
 
351w is a dog until you remove the 289/302 heads and put something that flows on then they wake up a ton. Even 1969 351w 4v (yes Windsor 4v heads) are too small for a 351. My dad has a stock stroke 351w with TFR R heads, solid roller, makes 600hp. Too bad its been on a stand for over 20 years.

The one that wins is the one with the most R&D and money invested.
 
Locomotion said:
Hot Rod (I believe) did a rule limited build of each and put them in 3,400 lb cars for ET comparisons many years ago. Mopar had a 360 in a blue Duster. It ended up the fastest. I don't recall the year.
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I think that was a crate motor comparison where they put the available crate motors from each manufacturer in a similar car.

HOT ROD 1992 OCT - CRATE ENGINE SHOOTOUT, VETTE, GTO - 1990-1999 - JIM'S MEGA MAGAZINES

Sure seems like Hot Rod did an article where they tried to build a 340, 350 and 351 to stock specs and compared them though.
 
If you made everything as even as possible, it comes down to air flow in and out with the key to these engines being the cylinder heads.

If you take advantage of our .904 lifter diameter where the other two can not, you would have a good edge in what is otherwise all as delivered stock engines for this comparison.

The Ford Cleveland 4V head is that engines strong point which pretty much buries everyone else’s head. That would be a tough one to overcome on a “A Cast Head.”
 
1WildRT said:
Along with a 351M... Plus the 351C 2V or the 351C 4V or the Ram Air/ Boss 351

Also depends if it's a LT-1 or a Goodwrench rebuild...

And it depends if it's a 68-71 340 or a 72-73 340 with dished pistons...
Click to expand...

72 and 73 340's were flat tops. No dish
 
rumblefish360 said:
If you made everything as even as possible, it comes down to air flow in and out with the key to these engines being the cylinder heads.

If you take advantage of our .904 lifter diameter where the other two can not, you would have a good edge in what is otherwise all as delivered stock engines for this comparison.

The Ford Cleveland 4V head is that engines strong point which pretty much buries everyone else’s head. That would be a tough one to overcome on a “A Cast Head.”
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Look at NASCAR. How many times were Ford and Chrysler penalized for being too fast? Guess how many times they added weight or messed with their aerodynamics to Chevy?

The heads will dictate the pecking order, led by the 351 Cleveland 4 barrel heads, 340 heads, poor Chevy guys never had a chance.
 
The crate motor shootout was Dick Landy on the duster if i remember right ?
I believe it was the original 360/380
Flat tappet crate motor.
 
Like stated, I think the OP is interested in bore/stroke ratio comparisons. Once you change the cam, compression, valve size. It’s not the same engine as you started with. The true answer on which is “better” when it comes to getting EVERYTHING out of a 340 or 350 or 351 etc comes down to head flow. How much can you get out of the head with max effort port work. Most of the other parts will support a surprising amount of power. Again it’s no longer a 340 or 350 or 351.
 
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A true blue printed small block challenge. Would be interesting. You can change NOTHING! I might be bias, but 340.
 
66fs said:
Look at NASCAR. How many times were Ford and Chrysler penalized for being too fast? Guess how many times they added weight or messed with their aerodynamics to Chevy?

The heads will dictate the pecking order, led by the 351 Cleveland 4 barrel heads, 340 heads, poor Chevy guys never had a chance.
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If they make GM and Ford use OE lifter diameters the Chrysler will whip them both. Even if it’s a roller lifter.
 
66fs said:
Look at the cams Chrysler used compared to Ford or Chevy. We got more done with less cam, stock.
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Meh, not really. Ford ground their cams ridiculously retarded and right in the muscle car era. They sucked. Had they not done that, they wouldda been a contender.
 
Of course the Mopar would win. All things being equal, the largest displacement small block would win. That would be the 360. Like said above the valve train would be more stable with the larger diameter lifters too.
 
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