To steal from rrr, it could probably pull a greasy string out of a cat's ***, but it will need a tail wind and maybe a downward slope.
I've been wanting to use that line for a while now. LOL
Mild 383 build
- Thread starter Shorty Thompson
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I've been wanting to use that line for a while now. LOL
Just stopping by, you guys haven't got this 383 built yet? 
Not mass, larger piston more surface area for force to be applied. When people see a 400 B engine vs a 408 they see 4" greater torque multiplication over the 3.38", but fail to recognize the greater force the 4.34" piston will have over the 4" piston to be multiply by the crank in the 1st place.
Again never argue against his 3800 stall recommend or for the OP to run a 292 cam.
He gave no CR numbers to work with, I gave a half joking shot in the dark answer to a question I wasn't even talking about, again I was talking about torque and cid.
Plus I don't see any evidence I'm necessarily wrong, the cam specs for the xe285hl and Mega 292 are fairly similar, 9.2 cr ain't considered high compression the engine at 3000 rpms is still making more than stock and we don't exactly know how much gain going to 10-10.5 from 9.2 will add, rule of thumb is like 3-4% maybe is maybe it ain't, all I know fair size cam in this relatively low cr engine didn't kill the bottom end.
I got a 360 (380hp crate). 9:1 cr 288/292 cam 108 2800 stall and 2.94 gears is it the best it can be no, still burn rubber and is fun I'm sure more stall and gears will make night and day difference but till then it is fine. Not saying/recommend the OP should run a 292 cam with 3000 stall and 3.73-4.10 gears but if he did probably wouldn't be the end of the world and can always do a converter swap down the road.
Everything doesn't always have to be prefect from day one.
Can we move on now?
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I would like to try the 440 piston in a 383. Especially at close to .125 over. That piston size is readily available. That would definitely unshroud the valves in aluminum heads. So then I guess that a 400 build would be a better choice with .030 over bore. Kim
Since he isn't dealing with an A body, he can always just do a 440 and still change the spark plugs. Would that be easier for a starting point?
It's much like the 318/360 argument for the small block guys.
I love the 318 and the 383, buuuuttttt...
Redheads with big tits are always the bett...
Sorry, got a little distracted. A bigger engine is generally going to be a better starting point.
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PRH
Well-Known Member
“Mild” 383…….
Pretty straightforward………
The short block sounds like it’s already sorted out.
Cam, for use with an 11” converter, something like an XE274 or PP274
Dual plane intake, 650-750 carb, headers
Heads can be pretty much any factory head with a decent valve job/recon/surface to 80cc/blended bowls(240+).
If done correctly……. Should in the 400hp range.
Pretty straightforward………
The short block sounds like it’s already sorted out.
Cam, for use with an 11” converter, something like an XE274 or PP274
Dual plane intake, 650-750 carb, headers
Heads can be pretty much any factory head with a decent valve job/recon/surface to 80cc/blended bowls(240+).
If done correctly……. Should in the 400hp range.
They are pretty thick. In fact, I remember somebody on here saying that the 400 was an overbored 383......but since the 400 has its own series of casting numbers and it was produced well after the 383, I don't know if that's factual or not.
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You guys are awesome, truly awesome. Makes me wanna jump right up and spend a bunch of money, but not just yet. I got 3 sets of heads that I have to make/take a stand on which set to go with, or look for another set.
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Kim, just get a ,060, 440 slug and be .135 over.
Newbomb Turk
Well-Known Member
This place will spend your money like a dime store hooker on meth.
And we love doing it and we brag about it.
Gomer Pyle
Member
They are pretty thick. In fact, I remember somebody on here saying that the 400 was an overbored 383......but since the 400 has its own series of casting numbers and it was produced well after the 383, I don't know if that's factual or not.
The 400 probably has a bit more, I have what was an unbored 400 that was given to factory sponsored SS racers. I bought it from a friend who is a retired east coast Super Stock racer that had Chrysler sponsorship back in the 70s and 80s, he ran a 383 in SS/GT, he had 5 of them I think and this was the last one left. He had it bored to 4.25 and it was put in his friends pickup truck for a few years to stabilize it with many heat cycles. I didn't check it with my sonic checker but he gave me a sheet which I have somewhere and at 4.25 bore it is about .300" thick everywhere. I bought it for my Super Stock 383 70 Challenger project which I haven't gotten to yet. I decided to build a Stock Eliminator 383 for it as I had a nice set of legal Ross pistons. I just finished decking it and when I get caught up with the engines I currently have buyers for and the one for the clunker 62 Dart, I'll assemble the Stocker 383, it's a 69 block that I filled with Halco machine grout and similar the 65 block for the Dart it's mostly in the .200" range at the major and minor thrusts at .060" over.
That's a lotta meat. I have a slant 6 block that sonic tested over .375 at the thickest and right at .300 at it's thinnest.
In post #78, the example of the larger piston, more force on the crank......is not correct, for the same cubic inches.
[1] If two engines have the same cubes, say 400, & 10:1 CR, then the combustion chamber volume is the same for both, 5.6 cu in.
[2] Bore & strokes can be different. The engine with the bigger piston has the expanding force of the burning mixture spread over a larger area, so less force per sq in with the bigger piston. The engine with the smaller piston has the force concentrated over a smaller area, so more force per sq in.
[3] If the 'big piston' theory in post #78 was correct, nobody would use a small bore/long stroke combo.
[4] Finally, if you take a 400 Pontiac with a 4.120" bore & 3.75" stroke. And a 400 Chev 4.125" bore, 3.75"stroke. Both have the same stroke but the Chev has a shorter rod. This means that the Chev piston is higher in the bore when the rod is at 90* to the crank throw where it gets maximum mechanical advantage. Since it is higher in the bore, it is seeing greater force from the expanding gas than the long rod engine, all else being equal.
[5] There is a reason that stroker engines perform so well...
[1] If two engines have the same cubes, say 400, & 10:1 CR, then the combustion chamber volume is the same for both, 5.6 cu in.
[2] Bore & strokes can be different. The engine with the bigger piston has the expanding force of the burning mixture spread over a larger area, so less force per sq in with the bigger piston. The engine with the smaller piston has the force concentrated over a smaller area, so more force per sq in.
[3] If the 'big piston' theory in post #78 was correct, nobody would use a small bore/long stroke combo.
[4] Finally, if you take a 400 Pontiac with a 4.120" bore & 3.75" stroke. And a 400 Chev 4.125" bore, 3.75"stroke. Both have the same stroke but the Chev has a shorter rod. This means that the Chev piston is higher in the bore when the rod is at 90* to the crank throw where it gets maximum mechanical advantage. Since it is higher in the bore, it is seeing greater force from the expanding gas than the long rod engine, all else being equal.
[5] There is a reason that stroker engines perform so well...
Proof ?
If this was true a longer stroke engine of similar displacements would always produce a very noticeably higher lbs-ft per cid of similar level of an build of engine. If it did it would break the law of "energy cannot be created or destroyed" why some's belief in torque as some kind a bonus power is also false.
Torque per cid is somewhat consistent/predictable for a given level of build.
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Proof?
First one is common sense. Like I said, if a big piston had more force on it, nobody would use...or design..... an engine that had smaller bore/longer stroke. Particularly where efficiency & economy are important such as commercial vehicle engines....which use long stroke engines.
At short notice......
Get a wet, soft grain of rice & put in on a table. Put a house brick on the grain, end on, & the grain is crushed. Spread wet rice over the table the area of the brick. Put the brick on the rice; the rice might compress but it won't be crushed because the same force [ weight of the brick ] is used in both cases, but concentrating the same weight [force ] over a smaller area produces higher pounds/ per area.
The longer v shorter stroke only looks at mechanical advantage. Not air flow. At lower rpms, a short rod moves away from TDC more abruptly than a long rod engine. This generates more vacuum in the cyl, vacuum being the medium at lower rpms that draws air into the cyl.
At higher rpms where you start to get some ram/inertial tuning, this abruptness can affect flow into the cyl, so the long rod is better.
First one is common sense. Like I said, if a big piston had more force on it, nobody would use...or design..... an engine that had smaller bore/longer stroke. Particularly where efficiency & economy are important such as commercial vehicle engines....which use long stroke engines.
At short notice......
Get a wet, soft grain of rice & put in on a table. Put a house brick on the grain, end on, & the grain is crushed. Spread wet rice over the table the area of the brick. Put the brick on the rice; the rice might compress but it won't be crushed because the same force [ weight of the brick ] is used in both cases, but concentrating the same weight [force ] over a smaller area produces higher pounds/ per area.
The longer v shorter stroke only looks at mechanical advantage. Not air flow. At lower rpms, a short rod moves away from TDC more abruptly than a long rod engine. This generates more vacuum in the cyl, vacuum being the medium at lower rpms that draws air into the cyl.
At higher rpms where you start to get some ram/inertial tuning, this abruptness can affect flow into the cyl, so the long rod is better.
So you don't know, but are guessing that I'm wrong lol
No,
I have just proved you are wrong [ you asked for proof, remember... ] but you don't 'get' it.....
And the above example has nothing to do with energy being created or destroyed. Energy can, & does, get converted to different forms of energy, which is exactly what is going on here.....
Chemical energy [ burning mixture ] gets converted to heat, which gets converted to mechanical energy [ force on piston crown ]. There are always some losses with energy conversion, but it is not destroyed.
I have just proved you are wrong [ you asked for proof, remember... ] but you don't 'get' it.....
And the above example
Chemical energy [ burning mixture ] gets converted to heat, which gets converted to mechanical energy [ force on piston crown ]. There are always some losses with energy conversion, but it is not destroyed.
You didn't prove ****, believe what you want.
If you don't see how this applies obviously you don't get it, maybe focus on helping the OP.
Gomer Pyle
Member
That should take a good size over bore, is it a 60s or a later block.
273,
If your BS was correct, everybody would be building engines with 7" pistons & 2"stroke. Oh, the free hp because of the large piston area!!!!
The rubbish you posted in post #78, you posted a few weeks back. I thought I will let it go. But then you repeated it....
One more try for the dumb: you hit a two inch nail into a piece of wood with one hammer blow. The hammer blow [ force ] represents the force from the burning mixture. Now get a piece of steel rod, about 5/16 " thick [ old p'rod ] & grind a point on one end [ like a nail ]. Using the same force on the hammer, hit it. It does NOT go into the wood as deep as the thinner nail even though the same force was used because the force was spread over a greater area.
If your BS was correct, everybody would be building engines with 7" pistons & 2"stroke. Oh, the free hp because of the large piston area!!!!
The rubbish you posted in post #78, you posted a few weeks back. I thought I will let it go. But then you repeated it....
One more try for the dumb: you hit a two inch nail into a piece of wood with one hammer blow. The hammer blow [ force ] represents the force from the burning mixture. Now get a piece of steel rod, about 5/16 " thick [ old p'rod ] & grind a point on one end [ like a nail ]. Using the same force on the hammer, hit it. It does NOT go into the wood as deep as the thinner nail even though the same force was used because the force was spread over a greater area.
Newbomb Turk
Well-Known Member
Great logic if you’re driving nails. There is a formula for that.
It’s:
P
L
A
N
P is PRESSURE
L is length
A is AREA
N is dammit I forget.
Anyway, it’s PRESSURE exerting FORCE on the AREA of the piston.
So…if you put 100 pounds of pressure on a 4 inch piston and that same 100 pounds on a 5 inch piston.
Which makes more power?
Why would that be ? My position was that torque is gonna be about the same for a given displacement no matter what the bore to stroke ratio one doesn't really have an upper hand over the other.
I don't think this the best analogy but it will do. Since even it shows your wrong.
The 5/16 rod (piston) doesn't have to go into the wood as far cause for the same size displacement with a larger piston (5/16 rod) is always gonna be pared with a shorter stroke (doesn't go into the wood as far) than a smaller bore with a longer stroke aka thinner nail deeper in the wood (longer stroke).
He assumes that a bigger bore will see less pressure.
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