408 Stroker vs RV 440

[Dusty 997]

Thinking about building another motor.

I'm debating on turning my 360 magnum into a 408 stroker vs snagging a cheap/free RV 440 and basically doing top end, alum heads, intake cam ext.

Looking into pricing, i dont see what id call a massive difference either way. Which one do you think would be more fun for street use and maybe some stoplight to stoplight action when nobody's looking

I saw some engine masters clips on youtube where a 440 RV motor responded really well to just a top end build and had a pretty damn impressive torque curve/powerband.

It seems to me that the 440 makes about the same power down low as my current 360 magnum makes at the mid-top end, but ive also heard that the 408 strokers can be real torque monsters too.

weighing pros and cons, i think the stroker build would be easier as getting it to fit is a non issue and accessories/linkages ext would all remain the same. in favor of the 440, the idea just sounds really friggin cool...

Im always getting asked "does it have a 340?" and it would be funny to say no, it has a FOUR FORTY.


Looking for input either way from folks who have gone either route.

 

[gzig5]

Im always getting asked "does it have a 340?" and it would be funny to say no, it has a FOUR FORTY.

They make a 4.25” stroke crank that should get you to 440”.

Personally I’d do the stroker but it really depends on what heads you are willing to put on it.

 

[33IMP]

For me, it would depend on what kind of parts I already had.
And also, what chassis I was gonna use, and how much room it has.
Early A-body already set up for a small block, and have a small block trans? 408, no brainer.
B or E body with room, and I've got a big block trans? 440 rv 100%..

 

[33IMP]

They make a 4.25” stroke crank that should get you to 440”.

Personally I’d do the stroker but it really depends on what heads you are willing to put on it.

Or you could do the 4.180 stroke, and call it a 426.

 

[273]

What top end would you run on the 408 ?

 

[273]

Plus what gears and stall you willing to run ?

 

[Plymouth 65]

408 with some good flowing heads. 65

 

[273]

If your also gonna buy a top end for the 408 also aka a complete build, you could just also complete build a 440 and stroke it too (500+ cid)

 

[TT5.9mag]

Put a turbo and 15psi on the 360 magnum and it’ll blow both of the other two options away. And the drivability won’t change at all off boost.

 

[Demonx2]

You're probably aware but the 408 has a 4" stroke vs the 440's 3.75" stroke. The 408's arm alone will win the torque battle quite handily. As for power, that depends on what heads, cam, etc.

I have a 408 in my avatar (11.0's) and a 440 in my 69 Charger (mid 12's). My 408 would eat my 440 for lunch. And I'm a big block lover!

A body? 408. B or E body? BBM and build it accordingly.

 

[273]

You're probably aware but the 408 has a 4" stroke vs the 440's 3.75" stroke. The 408's arm alone will win the torque battle quite handily.

Displacement is the main ingredient of torque, longer stroke don't automatically mean more torque, bigger bore (surface area) of the 440 equals more force in the 1st place to be multiplied by crank.

 

[Dusty 997]

If your also gonna buy a top end for the 408 also aka a complete build, you could just also complete build a 440 and stroke it too (500+ cid)

Yeah...thought about that too

 

[junkyardhero]

there's not such thing as a free cat...

that chonk block is going to eat up budget in a rapid manner: exhaust, motor mounts, transmission, throttle/trans linkages, radiator (likely). then add all the stuff to zip it up: intake, distribuitor, carb, cam, heads.

and if you're going that far? might as well rebuild it... so best case scenario a re-ring with a hone and a hot tank? or you pop for the full boat an it's pistons and cutting the block?

i'm never one to shy away from cubes, but when you already have the supporting cast in place the "sensible" play is stroking the mag (or forced induction). but when are we ever sensible?

 

[Dart Frog]

For me it would depend on what my power ceiling is, what I mean by that is you can build a 500 horsepower 500 ft lb torque small block stroker with relative ease but as you search for more horsepower head selection is better for a 440 and the block platform is just stronger over all.also it has the advantages of more head bolts for easier cylinder head sealing yes there is a small weighted advantage in a small block. So I guess I would say for the street and occasional strip car I personally would stay with the small block stroker but if I was building a car for the strip I would strongly consider a B or RB platform.

 

[Demonx2]

Displacement is the main ingredient of torque, longer stroke don't automatically mean more torque, bigger bore (surface area) of the 440 equals more force in the 1st place to be multiplied by crank.

Well there's plenty of variables for sure! And you are correct that nothing is "automatic." But if the displacement is the same/close, stroke will win in the torque dept.

Keep in mind that OEM's do all of the initial work on a new engine via computer analysis, and when we wanted to make a higher torque engine, the first thing we look at is stroke. We could (and did!) run myriads of ways to make more torque or power. Yes, the increased displacement due to stroke will also get a little more power too but torque is the main thing. With the same combustion system (ports/chamber/cam), the indicated power for the increased stroke will go up due to the displacement/increased breathing. And at the lower torque peak rpm's, when you subtract off the higher friction power due to the longer stroke/piston speeds, you still get a bunch more torque. But push those speeds up to the power peak area, and when you subtract off the higher friction power (function of piston speed squared), it takes a bigger bite out of the higher indicated power hence why the peak power does not go up as much when you stroke an engine. Peak torque yes, peak power not as much. Lots of variables and nothing is automatic hence why so many hundreds of combinations are evaluated.

I could give you examples but I don't get into which OEM I worked for so I'll just leave it at that.

 

[Dusty 997]

Good points. Got me leaning towards stroker.

 

[496 polara]

Build the 408 and pickup the 440 for later.

 

[Dusty 997]

Build the 408 and pickup the 440 for later.

you sound like my Gunshop dealer "get em both!"

 

[496 polara]

you sound like my Gunshop dealer "get em both!"

You said cheap or free,and I have never heard that from my gun shop.

 

[fishmens67]

500tq 500hp is pretty easy with a 440 based 500 or 512, just about off idle. lol
I have to laugh every time I hear the 408/440 question, there is no comparison.

 

[Bewy]

I would go with the stroker....
Much lighter internals will help acceleration. And overall weight saving.

 

[Icetech]

I am going the 408 route.. but i kinda wish i had done a 400 or 440 with good heads... the 408 will end up costing me twice as much... BUT.. i like the small block more (it's my first one)

 

[Dusty 997]

You said cheap or free,and I have never heard that from my gun shop.

RV 440s go for anywhere from "free come get it off my property" to 200-300 bucks. Around here rural ohio is a gold mine for people who have acess to machineshops to clean up old blocks

 

[Icetech]

RV 440s go for anywhere from "free come get it off my property" to 200-300 bucks. Around here rural ohio is a gold mine for people who have acess to machineshops to clean up old blocks

here a RV motor is 700-1000 usually.. rarely see them lower.. there are only 2 machine shops near me.. that's the hard part

 

[Dusty 997]

Ouch! i turned down two free ones just this year because i always thought they were boat anchors and not worth loading up and building unless you were planning on completely gutting the bottom end and adding high compression pistons ext. to get them to the same specs as the pre 72 desirable ones. But those dyno results i saw off just a top end build impressed the hell out of me. Amazing curve and an assload of torque even off idle.