Is building a stroked 318 better than a stroked 340/360?

[Dale Davies]

whats the diff in price between the 360 n say a 5.7 GEN III from a ram ?

That depends on whether you will run carb or EFI. Yes there is the injected 5.9l but a fair number of the carb versions around also.
The Gen 3 is injected with DoD and variable cam timing. Those two are trouble spots and should be deleted. Then if you want a carb, you need an ignition controller for sparks. Once you choose EFI you need to be proficient with electronics and wiring. There are kits out there, but will add cost.

 

[DionR]

That depends on whether you will run carb or EFI. Yes there is the injected 5.9l but a fair number of the carb versions around also.
The Gen 3 is injected with DoD and variable cam timing. Those two are trouble spots and should be deleted. Then if you want a carb, you need an ignition controller for sparks. Once you choose EFI you need to be proficient with electronics and wiring. There are kits out there, but will add cost.

I disagree with VVT being deleted, it adds a fair bit to the motor. And honestly, I think a carb’ed G3 is a waste of time. Not that there aren’t advantages even with a carb and deleting VVT, just that the EFI and VVT are significant advances. Maybe it makes sense on a race motor, but in my opinion not for a street motor.

Deleting MDS I agree with, just not enough of an advantage and anything but the OEM auto would need it removed anyway.

BTW, the only ignition module available for a carb’ed G3 is for the pre-Eagle 5.7 and the 6.1. Later G3’s like the 6.4 can’t be run on them, at least not without changing the crank tone ring. Maybe a megasquirt setup could be built, but the MSD controller can’t read the later tone ring. And they are like $800 after you add the harness you have to buy separate.

 

[Dale Davies]

I disagree with VVT being deleted, it adds a fair bit to the motor. And honestly, I think a carb’ed G3 is a waste of time. Not that there aren’t advantages even with a carb and deleting VVT, just that the EFI and VVT are significant advances. Maybe it makes sense on a race motor, but in my opinion not for a street motor.

Deleting MDS I agree with, just not enough of an advantage and anything but the OEM auto would need it removed anyway.

BTW, the only ignition module available for a carb’ed G3 is for the pre-Eagle 5.7 and the 6.1. Later G3’s like the 6.4 can’t be run on them, at least not without changing the crank tone ring. Maybe a megasquirt setup could be built, but the MSD controller can’t read the later tone ring. And they are like $800 after you add the harness you have to buy separate.

VVT does gain performance by advancing the cam at low RPM and retarding it as the revs come up. Problem comes up with people not changing oil frequently enough and the solenoid gets plugged or the phaser fails. Not as much a problem as the DoD BS with failed lifters and sillynoids. All OEMs seem to be having trouble with their DoD systems no matter how they call it.
Carbing a G3 is definately not worth it, but you better get everything from the donor. LA and Magnum are a different proposition.

 

[Mean416]

Bore/stroke/rod ratios don't mean squat for the Average build.

Stop worrying about that stuff and think about the big stuff. Displacement, airflow are big things.

The last thing Mopar had in mind was the 318, when the G3 hemi was designed.

 

[DionR]

The last thing Mopar had in mind was the 318, when the G3 hemi was designed.

Didn't mean to imply they used the 318 as a basis or anything. Just pointing out the interesting overlaps in bore and stroke.

 

[273]

Bore/stroke/rod ratios don't mean squat for the Average build
Stop worrying about that stuff and think about the big stuff. Displacement, airflow are big things.

True, but if you can design them into your build without too much added expense doesn't hurt.

The last thing Mopar had in mind was the 318, when the G3 hemi was designed.

But really the rotating assembly is basically similar, they started with the basics bones of the A engine and built upon it. Just really mainly different head packages from poly, wedge, magnum, hemi on the similar basic rotating assembly. How I look at it anyways.

 

[DionR]

whats the diff in price between the 360 n say a 5.7 GEN III from a ram ?

Here's my running total so far. I will probably have rings and bearings into the motor plus a car timing chain cover and the FEAD parts so far from a complete costing. Plus I plan to buy HP Tuners so add $500-600 for that.

Core 2017 Hemi (Truck)	$400.00​
Holley Swap Headers	$485.95​
Holley Motor Mounts	$226.75​
Holley Oil pan w/ pickup	$475.18​
Used PCM	$100.00​
OE harness(es)	$120.00​
6.4 cam and springs	$401.29​
Dipstick and PS hoses	$137.94​
Gas Pedal	$20.00​
90 degree adapter	$167.76​
6.4 Intake (used)	$310.37​
SPECTRA CR11E gas tank	$158.79​
Used C5 Camaro fuel module	$75.00​
GTO tank to cut ring out of	$100.00​
VaporWorx FPRAGM5	$14.99​
Total	$3,194.02​

 

[Newbomb Turk]

Bore/stroke/rod ratios don't mean squat for the Average build.

Stop worrying about that stuff and think about the big stuff. Displacement, airflow are big things.

The last thing Mopar had in mind was the 318, when the G3 hemi was designed.

Yeah, bore/stroke/rod ratios DO matter, regardless of what the nonsense on the internet says.

If you just look at rod/stroke ratio and how it affects cam timing. Saying it doesn’t matter is just wrong.

It’s why there is so many under achieving strokers are out there. They added more stroke than they can feed, killed the rod ratio and had to handicap the cam to try and save it.

Look at a Pro Stock engine. You’ll see the rod ratio is right around 1.7:1. Listening to some out there, that’s very high.

It matters. Giving up bore size is also dumb. The same pressure across a bigger bore makes more power.

 

[70coupe]

Over here in Aus there a lots and lots of 318/390 strokers, and lots of guys build 318s as 340s are virtually non-existant and 360 cores are drug money.
Hell, even 318 cores have adopted post covid pricing - Around $1500aud (1000 USD) for a clapped out rebuilder!

 

[Dale Davies]

Yeah, bore/stroke/rod ratios DO matter, regardless of what the nonsense on the internet says.

If you just look at rod/stroke ratio and how it affects cam timing. Saying it doesn’t matter is just wrong.

It’s why there is so many under achieving strokers are out there. They added more stroke than they can feed, killed the rod ratio and had to handicap the cam to try and save it.

Look at a Pro Stock engine. You’ll see the rod ratio is right around 1.7:1. Listening to some out there, that’s very high.

It matters. Giving up bore size is also dumb. The same pressure across a bigger bore makes more power.

A lot depends on your intended use and expectations with budget in mind. A stroker should use longer conrods to keep close to the original rod to stroke ratio. The cheap way for a Chevy 383 is to use the 400 rods and syroker crank. Rod to stroke ratio is not advantageous unless you are building a low RPM pump or generator engine and you are looking for torque. Years ago one of the magazines did a multi issue test, starting with a 350 and then installed a stroker crank with 5.565" rods, being careful to maintain the CR the same. Then they put 5.7 rods in with pistons to match. Cam was the same. The short rod 383 made a bit more power and torque but not what you would expect. The long rod 383 picked up a bit of torque and power. Now the larger displacement needs a bit more cam to really shine. One thing noticed was the long rod engine was quieter.
With the short rods the piston moves away from TDC quickly and should develop good vacuum in the cylinders. Larger intake valves and higher lift should let that vacuum make its way to the carb. LSA is affected slightly, like 0.25°.

 

[Newbomb Turk]

A lot depends on your intended use and expectations with budget in mind. A stroker should use longer conrods to keep close to the original rod to stroke ratio. The cheap way for a Chevy 383 is to use the 400 rods and syroker crank. Rod to stroke ratio is not advantageous unless you are building a low RPM pump or generator engine and you are looking for torque. Years ago one of the magazines did a multi issue test, starting with a 350 and then installed a stroker crank with 5.565" rods, being careful to maintain the CR the same. Then they put 5.7 rods in with pistons to match. Cam was the same. The short rod 383 made a bit more power and torque but not what you would expect. The long rod 383 picked up a bit of torque and power. Now the larger displacement needs a bit more cam to really shine. One thing noticed was the long rod engine was quieter.
With the short rods the piston moves away from TDC quickly and should develop good vacuum in the cylinders. Larger intake valves and higher lift should let that vacuum make its way to the carb. LSA is affected slightly, like 0.25°.

Are you forgetting cylinder heads and how they are affected by rod/stroke ratio?

I like that you can repeat what’s on the web, but in the real world if you are cylinder head limited, and virtually every small block Chrysler stroker is, you can’t just piss away rod ratio. If you do, it changes cam timing requirements. And pulling the piston away from the head sounds good on paper, until you look at cylinder airflow demand and crank angle.

Then you have to think about ignition timing and about getting the mass fraction burn timed.

It all adds up. Saying something doesn’t matter is ignoring all the relationships between these parts and how they affect one another.

 

[Dale Davies]

Are you forgetting cylinder heads and how they are affected by rod/stroke ratio?

I like that you can repeat what’s on the web, but in the real world if you are cylinder head limited, and virtually every small block Chrysler stroker is, you can’t just piss away rod ratio. If you do, it changes cam timing requirements. And pulling the piston away from the head sounds good on paper, until you look at cylinder airflow demand and crank angle.

Then you have to think about ignition timing and about getting the mass fraction burn timed.

It all adds up. Saying something doesn’t matter is ignoring all the relationships between these parts and how they affect one another.

You did not read or did not comprehend!

 

[273]

Do you need great bore/stroke/rod ratios to build power obviously not but I imagine why most people here are Mopar fans is cause of Chryslers engineering of their engines, which bore/stroke/rod ratios are a huge part of that. I get it most people are not in highly competitive racing so cheap easy power is more than enough to do burnouts and run good ets etc... Eg. It's more important for most to build 450-550+ hp at streetable rpms that fit in a small block space hence the 408 instead of using a little more space and keep great B/S/R ratios and use a 383/400/413/426 which all could easily do that role.

 

[Mean416]

Bleeding edge racing engines (pro stock, F1, NASCAR, etc) really have no place in this conversation. They're different animals and drawing conclusions about what they're doing and saying hey I should do that on my old school Mopar. Will it hurt? Probably not. Will it have a significant effect? I.e. something that is measurable in any way, from butt dyno, real dyno, quarter mile times? I don't think so. Sure a few hp give or take. But that's the small stuff.

For those of you that disagree, find me one dataset where this stuff is apples to apples scientifically compared and shows a real result. If you can show that then by God I'll back pedal what I'm saying here.

But I doubt I'll see anything.

 

[Dale Davies]

Yeah, bore/stroke/rod ratios DO matter, regardless of what the nonsense on the internet says.

If you just look at rod/stroke ratio and how it affects cam timing. Saying it doesn’t matter is just wrong.

It’s why there is so many under achieving strokers are out there. They added more stroke than they can feed, killed the rod ratio and had to handicap the cam to try and save it.

Look at a Pro Stock engine. You’ll see the rod ratio is right around 1.7:1. Listening to some out there, that’s very high.

It matters. Giving up bore size is also dumb. The same pressure across a bigger bore makes more power.

True enough but sometimes ya hafta live within uour means. That likely means what upu have.

 

[Newbomb Turk]

Bleeding edge racing engines (pro stock, F1, NASCAR, etc) really have no place in this conversation. They're different animals and drawing conclusions about what they're doing and saying hey I should do that on my old school Mopar. Will it hurt? Probably not. Will it have a significant effect? I.e. something that is measurable in any way, from butt dyno, real dyno, quarter mile times? I don't think so. Sure a few hp give or take. But that's the small stuff.

For those of you that disagree, find me one dataset where this stuff is apples to apples scientifically compared and shows a real result. If you can show that then by God I'll back pedal what I'm saying here.

But I doubt I'll see anything.

You won’t see a bunch out there. Why would you? Why should someone do all the work and/or pay for it and post it?

It all matters. It’s all interrelated. You might find 20, maybe 30 hp and not spend a cent more IF you don’t ignore important **** like rod ratio and how it affects cam timing, how cam timing affects compression ratio and so on.

You can think and believe whatever you want, but saying geometry doesn’t matter is just silly. Or ignorant.

 

[Mean416]

You won’t see a bunch out there. Why would you? Why should someone do all the work and/or pay for it and post it?

It all matters. It’s all interrelated. You might find 20, maybe 30 hp and not spend a cent more IF you don’t ignore important **** like rod ratio and how it affects cam timing, how cam timing affects compression ratio and so on.

You can think and believe whatever you want, but saying geometry doesn’t matter is just silly. Or ignorant.

Lots of guys out there testing and posting plenty of good info and test results. It just so happens that what some folks are dying to believe, there's not much supporting evidence for.

 

[Newbomb Turk]

Lots of guys out there testing and posting plenty of good info and test results. It just so happens that what some folks are dying to believe, there's not much supporting evidence for.

Sure there is. You need to spend your money to find out. Or not.

 

[Newbomb Turk]

True enough but sometimes ya hafta live within uour means. That likely means what upu have.

I get that. There is a big difference between saying you don’t have the money to buy parts and saying geometry doesn’t matter. If you can’t afford to do it that’s not an engine builder issue. That’s a consumer issue

 

[Mean416]

I'm happy for people to have religious faith, if that's what they want. But I don't have "faith" in whatever Smokey Yunick and Dyno Don and David Vizard etc etc did back in the day, as it applies to everyday sub 600hp street/strip engines.

I'm not saying there's no relevance in this stuff. Just that it's not relevant to us.

 

[Newbomb Turk]

I'm happy for people to have religious faith, if that's what they want. But I don't have "faith" in whatever Smokey Yunick and Dyno Don and David Vizard etc etc did back in the day, as it applies to everyday sub 600hp street/strip engines.

I'm not saying there's no relevance in this stuff. Just that it's not relevant to us.

It’s not relevant to you because you dont want it to be. Has nothing to do with faith. It’s called testing. You need to do your own testing, or just keep your opinions to yourself. Your opinion doesn’t line up with actual testing and racing.

 

[Mean416]

Hmmm. And yours does?

You can't back up one iota of what you're talking about. I'm just calling you out, and you're butthurt.

Like I said, bring some real back to back data out and it'll be relevant.

Let's say you take a 360. Get a set of stock rods and pistons, a set of 6.0 rods and custom pistons, and a set of 6.2 rods and custom pistons.

Which one will be the best and by how much? I bet there's not a 10 hp spread across the three.

10hp can be an advantage in some racing situations. Which is why it's relevant for high end racing situations. But not for us mortals.

 

[Newbomb Turk]

Hmmm. And yours does?

You can't back up one iota of what you're talking about. I'm just calling you out, and you're butthurt.

Like I said, bring some real back to back data out and it'll be relevant.

Let's say you take a 360. Get a set of stock rods and pistons, a set of 6.0 rods and custom pistons, and a set of 6.2 rods and custom pistons.

Which one will be the best and by how much? I bet there's not a 10 hp spread across the three.

10hp can be an advantage in some racing situations. Which is why it's relevant for high end racing situations. But not for us mortals.

Here‘s where you miss it. You’re betting with no experience.

Changing the rod ratio SHOULD make you change your cam timing.

Like I said above, and you can’t hear it is that it all adds up. You’ll walk away from 30 hp and I won’t do it. No need to.

Prior planning on a build will end up costing less, making more power and will drive better than if you just get into a catalog and start ordering parts, or worse yet hanging on the internet where everyone with a computer can play the hero and tell someone how they build their **** when they didn’t build it, they got on the internet and listened to another hero who got his build from another hero.

 

[Mean416]

Where's your experience? Do YOU have back to back data testing rod ratios? I doubt it. It would be interesting. But I doubt it.

 

[Newbomb Turk]

Where's your experience? Do YOU have back to back data testing rod ratios? I doubt it. It would be interesting. But I doubt it.

Sure do. Lots of data. You get to pay for it if you want it.

Better yet, since you are arguing like a pro on this YOU need to post up how it doesn’t matter. Not your anecdotal bullshit about what you think. Post up your testing results that says it doesn’t matter.

You can’t because you don’t test. That’s why you keep arguing.