360 vs 383

383 or 360 ?

  • overall, 383 all things considered

    Votes: 33 60.0%

  • overall, 360 all things considered

    Votes: 22 40.0%
  • Total voters
    55
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318willrun said:
That would be a lot of what vehicle the engine is in. For sure, the small block with Doug headers will be an orbit or two away easier than a BB with headers in a A-body.
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But on the line of mechanics and ease of work'n on them, if we just look on top.......
the 383 intake swap is a marvel compared to the small block, as the 383 has no coolant through the intake, less bolts, and the gasket can be re-used right in place. Also, distributor swapping/tuning on the 383 is obviously easier up front than the rear. Water pump also, just 4 bolts and a small pump. Also, we could head down the block to the oil pump and oil pan ....
 
318willrun said:
But on the line of mechanics and ease of work'n on them, if we just look on top.......
the 383 intake swap is a marvel compared to the small block, as the 383 has no coolant through the intake, less bolts, and the gasket can be re-used right in place. Also, distributor swapping/tuning on the 383 is obviously easier up front than the rear.
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This is my first small block and i honestly find pretty much everything easier on a BB... timing cover, oil pan.. water pump. intake.. dist... everything.
 
Icetech said:
This is my first small block and i honestly find pretty much everything easier on a BB... timing cover, oil pan.. water pump. intake.. dist... everything.
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Right, but in the end, if you have a Duster, you still have to install the engine and hook up the headers (and header choices)... and in this area the 360 is a mile ahead.
 
Profoundly deep subject. My thoughts on the matter, and I’m open to changing that.

Not a big fan of the 360, it just doesn’t have the small block characteristics of the 340 or teener. The mighty memorable 340, save those for the restoration crowd. My small block choice is the plentiful teener.

It is said that a increase in horsepower of an 1/8 inch over bore is equal to an increase of 1 inch of stroke so I’m favoring the nose heavy 383 in an A body and an appropriate proportioned bigger car or pickup which would be less noticeably nose heavy. Only difference for me is if you want to race around corners , then the small block may be the best choice.

As for bracket engines, who cares? Your racing against yourself and your dial in. Run what suits you.

And for all out race engines, there are aftermarket blocks and assemblies for that. Even in street racing, there is a guy or guys that show up with a trailered car that cleans everyone’s clock.
 
273 said:
Yes but a stock sbm weight is considered acceptable handling wise, so if a modded big block weighs similar to that should be acceptable also, now if building something like an auto cross car then the benefit of even less weight can be an advantage.
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Right, which is what I was inferring about using aluminum parts. It really is probably a wash nowadays. Case in point - I have a 470" short block with a Scat ultralight 3.91" stroke crank in it that weighs around 54lbs. The finished bob weight is 2,222 grams which is over a POUND less than a stock 440. Think abut that! That's not a couple ounces, that's a pound which is a ton of weight. Topped with aluminum heads and intake etc., I'm in small block territory in regards to front to rear weight balance.

Also, the bigger bore can mean less weight, especially with a larger overbore. I'd be willing to bet a .060" over 383 weighs pretty close to a .030" over 360.

360 also has larger mains than the 318/340 so it requires larger bearings and creates more frictional area. I've read plenty about racers using 360 blocks with bearing spacers to use the 340 main bearing size.

A good question to discuss might be why in 1971-2 the factory engineers decided to drop the 383 in favor of the 400 and while turning it into a gas-guzzling pig (in stock form) or conversely, why was the 340 similarly replaced with a lower-performing but larger displacement engine?
 
318willrun said:
Didn't want to derail stroked 340's thread any further. I think this is a really good comparison. I have both now, and in the past. Can we put aside our bias and speak facts, functions and possibilities?

Lets assume same car/gear/transmission & converter. Which do you like best in these 4 scenarios :

  1. 360 4bbl stock vs 383 4bbl stock.
  2. Mildly hopped up for the street
  3. Decently built bracket car engine
  4. Well built-high horsepower race engine.
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1. Can I cheat and say magnum 360? In an a body specifically I dont see the 383 being worth the difference in cost and size.
2. Same. 360 magnum.
3. Same 360 magnum. Every 383 block will need machine work. That's money I won't spend on a 5.9 block that will let me buy better heads.
4.383. Bigger is better and better flowing heads are available


My rule of thumb is bang for buck is always magnum 5.9 but if I were a legit racer or I need torque for a truck bigger is better.
 
rmchrgr said:
A good question to discuss might be why in 1971-2 the factory engineers decided to drop the 383 in favor of the 400 and while turning it into a gas-guzzling pig (in stock form) or conversely, why was the 340 similarly replaced with a lower-performing but larger displacement engine?
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Probably due customer demand for mid displacement engines 350-400 cid in the 70's.
 
I put a 440 into a '68 Valiant once way before swap parts were readily available as they are today. I love the ease of working on big blocks, but in an A body it takes up every bit of space. Changing plugs is easier if you can cut a hole in the inner fender near some plugs. That little engine compartment got hot too. Headers were a nightmare in that car and the only thing available back then was Hooker fenderwells with very low ground clearance. Only drove it around town, no racing.

I also put a Blueprint Engines 408 (stroked magnum 360) into my '70 Duster/727 with 3.55 gears. Very easy installation with a lot of space under the hood. Biggest issue I had was after changing the torsion bars I had to clearance the Dougs headers. Headers tucked up nicely with excellent ground clearance. BPE rated that engine on their dyno at 465HP. That car wanted to run. I got an honest 13MPG going 70-75 on the highway.

If I had to do it again in an A body, I would go hands down small block with all the aluminum 'trimmins.
 
rmchrgr said:
A good question to discuss might be why in 1971-2 the factory engineers decided to drop the 383 in favor of the 400 and while turning it into a gas-guzzling pig (in stock form) or conversely, why was the 340 similarly replaced with a lower-performing but larger displacement engine?
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EPA,SMOG,GOVERNMENT MANDATES. Had to go with lower compression,unleaded gas etc.
And yes a stock 78 400 was a pig and sucked gas. Best of 8 mpg.I had one in 1978. What a turd..
 
With the light weight of a big block with aluminum parts equaling the weight of a stock small block, the same light weight aluminum parts on a small block will weigh in/6 territory. So that argument is a non starter with me. It’s about hp per lbs of engine weight with running gear.
 
ch1ll said:
With the light weight of a big block with aluminum parts equaling the weight of a stock small block, the same light weight aluminum parts on a small block will weigh in/6 territory. So that argument is a non starter with me. It’s about hp per lbs of engine weight with running gear.
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I bet the average big block is making more hp per pound of engine weight, especially in a A Body.
 
Darter6 said:
EPA,SMOG,GOVERNMENT MANDATES. Had to go with lower compression,unleaded gas etc.
And yes a stock 78 400 was a pig and sucked gas. Best of 8 mpg.I had one in 1978. What a turd..
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Also rising insurance premiums for high performance cars.

One of my proudest carb tuning achievements was getting 13mpg out of a lo-po 400. it was in a heavy brick of a '70s, 2WD truck with 3.23 gears and a granny tranny truck 4 speed. The P.O. put a .484" MP cam in it with a stock bottom end. The pistons were almost .125" in the hole so it basically had no compression. Also had an RPM intake, headers and a Holley 750 vac. sec. Totally mismatched combo but somehow it ran. That 13mpg was without any vacuum advance in the distributor either so I may have done better had I tried to tune with it. But I digress.

Bottom line is that both the 360 and 400 in the '70s were just laughable with each having half or less the horsepower per their respective displacements but the 383 was really not that much better. To me, performance should mean the engine can rev past 5,000 rpm and like I said in my earlier post, the 383 in my Coronet would barely go past 4,300 even with my foot to the floor. That's despite having the factory 10:1 compression pistons slightly above deck and the 335 hp cam that was in Road Runners and Super Bees. Probably worn out to a degree but still you'd expect it to get closer to 5,000 rather than 4,000.

Prior to the performance car market boom, 383s were kinda like station wagon engines. The Golden Commando 383 was an exception but mostly they were pretty pedestrian.

There's certainly 360-based dirt track or Super Stock engines out there making close to 2hp/cube but I rarely if ever hear about 383-based engines putting up those kinds of numbers. 600, seems reasonable but 7-800... I don't think so.
 
rmchrgr said:
There's certainly 360-based dirt track or Super Stock engines out there making close to 2hp/cube,
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rmchrgr said:
but I rarely if ever hear about 383-based engines putting up those kinds of numbers.
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Cause most would start with 400/440 don't mean a 383 can't, it's got enough bore and can take most of the same parts.
rmchrgr said:
600, seems reasonable but 7-800... I don't think so.
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Torque at peak hp is around 90% and peak torque for this kind of build should be able to get around 1.4 lbs-ft per cid so 389 x 1.4 = 545 tq x 90% = about 490 tq @ peak hp, 700 hp x 5252 / 490 tq = 7,500 rpm
and 800 hp 8,575 rpm give or take depending on efficiency. Seems like possible rpm's and we know we have heads more than capable of these power numbers, A 400 would still need to rev similar, stroke would be the main thing to bring the rpms down whether it be 383,400,440 since the bore sizes are fairly similar.

Any engine running at similar efficiency making similar hp per cid would run at similar rpms.
 
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Since I am cheap, and only run factory heads, blocks, and usually intakes, I never noticed any big weight differentials or 383 A-Body lack of handling. Have you driven a factory big block A-Body? Theoretical BS as far as I'm concerned having driven HP 383 and 340 A-Bodies as daily drivers. Never cared for a 360. To be fair the poll should have been 360 HP 4 barrel and 383 HP 4 barrel. Heck, I passed on a new factory 360 HP 4 barrel Aspen because the 273 I was running was faster. The 383 has a forged crank, neutral balance, stronger block, better flowing heads, and is just a cam change away from being high performance with all that torque. If you can't get your 360 or 383 to pull past 4,000 rpm you should not be talking High Performance. No need to equalize torque convertors or gears. No rules on the street. If you want to spend all that coin on stroker assemblies and aluminum heads, go for it. I never felt the need for any of it.
 
In my experience, a 383 2bbl and 360 2bbl are so close in every way possible that I doubt I would have known which one was in the car by just driving, without opening the hood. Especially in C-bodies. But this is just the bottom of where both power plants were intended to be..... mules.
 
I had a '68 Fury III Police Package (build sheet verified). It came with factory disc brakes, dual exhaust, 383 commando, and dual mirrors. 727 of course. In low mileage-stock form it ran lower 15's with even the factory carburetor still on it. About 4400 lbs at the start line (no spare or jack, me in it). I thought that was respectful considering where the car dated and era.

We added 3.55's, a weiand intake and 750 holley and dropped down to 14.7's. About a half second drop. Not at all fast, but when all considered, respectful.
 
DionR said:
Won't the 383 always weight more than the 360 if they both have the same advantages of aluminum parts? The 383 has wider bore centers, taller deck and skirted block. Just more cast iron.

Not saying it makes a huge difference, but it sure seems like the 383 will always weight more.
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About 100 pounds more. The 440 about 150 pounds more.
 
273 said:
Yes but a stock sbm weight is considered acceptable handling wise, so if a modded big block weighs similar to that should be acceptable also, now if building something like an auto cross car then the benefit of even less weight can be an advantage.
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I always think it's hilarious how people always cry about 100-150 extra pounds.
 
RustyRatRod said:
I always think it's hilarious how people always cry about 100-150 extra pounds.
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It's not hard to find a 100 lbs difference right on the front between a Duster with A/C and power steering and a "no A/C w/Manual steering" car with the same engine. Not many say too much about the handling in those cases.
 
I'm Guessing most people wouldn't run a ritter block cause of it's weight then? I'm sure strangely people would have little problem running a 4.25" bore taller deck small block for better rod ratios for 4-4.25" crank with add weight for strength.
 
Not really germane to the discussion (the damn Germans got nuttin to DO wit it, Buford T. Justice), but the Chevy guys LOVE stroker 496 big blocks.
A stroked 383, to 4.310x4.25, is the exact same,bore/stroke as the Chevy, with a taller block, longer rod, and a better rod/stroke ratio.
It gives up only a little bore diameter and16 cubes to a 400/512.
 
So, does anyone or has anyone put a #1,2, or 4 main bearing in the back journal of a small block? Maybe 1/4” narrower, needed to grind a new bearing tang groove in the cap and block. Narrower bearing for less drag . This was right in the dc bible, right by the old flip the pistons backwards page. Guess this would be with the same thought as a 340 bearing spacer in a 360 that Bill Richardson sold.
 
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