Ok, so the shop that I will one day hopefully be getting a new motor from charges the same price for a 347 as they do the 331. I've always loved the uniqueness of the 331 and how it makes amazing power while being a relatively small displacement. I also like the very good bore/stroke ratio. My dilema is, would I be better off just stepping up to a 347 for the same price? I've never really done much reading on 347's, I only know that it's the max a 302 can be bored and stroked. I would assume that it's going to make more power if I build it identical to how I want my 331 to be. From what I've researched the 331 will make power between 2500 to 6500 RPM, does that sound unlikely for a 347? All in all I want to get the most bang for my buck, but at this point I'm still pretty much set on the 331 untill I figure out more. I know some of you guys have experience with both these engines, so lemme know your thoughts and opinions. Thanks
Paul
I think the 347 would out power it in every situation. But it is basically the max you can do. A 331 can at least be rebuilt. Just think about it this way, even with all the same parts, (heads, cam ect) the 347 will still make more power.
keep the standard bore of the block and put the 347 kit in it, would make it like 342 so if something happens you can atleast bore it out a little?
yeah same idea with a 306 max bored. so if something screws up the walls. that block is unless you sleav it . but roller blocks are plentyfull.
well. if you are goign to be pushing the engine alot, the 347 is the MAX it can go. so i are really at the limits of the block.. where the 331 is a good improvement, but you still have some block left. and the power won't be that much of a difference. a few hp.
you can get a 302 to more then just 306, 306 is only .030 over, ive seen but dont recommend people doing .060 to make it around 311.
Here is a really good article from MMFF on the 331. The extra cubes from the 347 will give you more torque but they have a reputation for being unreliable (piston rings). But those problems have been mostly fixed now with the newer kits.
http://www.dssracing.com/images/articles/331%20Ways%20to%20Waste%20an%20LS1%20PT2.pdf
Thanks, that was a good article. I'm basing my build off of the 200 MPH Mustang article that is in MM&FF, I'll just be using different heads and intake. They tried it once with a 347 and the guy wasn't satisfied with it. Either way, I wouldn't even be considering the 347 if it weren't for the fact that it is the same price. I think I like the fact that if I somehoe (God Forbid) mess up this motor, I still have leway to fix the block. And while the extra torque is nice, It won't be that large a number to make me want to switch. This is all still very far down the road however, so I'll keep my options in mind.
Thanks for all you replys.
While I don't have much practical experience with V8's, I've always liked the 331's...mostly because that while they have supposedly fixed the 347's oil burning problems, the wrist pin is still up there in the oil control ring and I don't care for that. Plus everyone gets a 347, it's different to get a 331 :dunno:
OK lets settle all of this at once
331= 30 over 3.275 stroke 5.315 rod
347= 30 over 3.400 stroke 5.400 rod
CHP 347= 30 over 3.400 stoke 5.315 rod
so with that being said go cubic inches the CHP kit does not have the oil ringsin wrist pin, however i have ran a 347 with wrist pin oil ring and no trouble, call Bruce at CHP 1-310-784-1010 and talk to them you can not beat their price, quality, customer service tell him Ron from Precision Tune sent you if you need any further info on what to build and how to make power with the right combo please contact me 734-776-5987 or rpm121370@yahoo.com
Ron
I've heard of a 3.47" crank being used. With a .030 over bore it gives 354...
I'd love to have one of the Man-O-War blocks that will take a .150+ overbore. I just can't see spending $2300 for a block though...
Still 4.15 x 3.4 = 368cu in...
I know a 372cu in version is available as a complete engine for $8500 or so from Summit..
I haven't heard anyone talk about piston speed. Anyway, a 331 and a 347 are both bored 0.030" over so...why is everyone talking about being able to rebuild a 331 and not the 347?...both would be screwed.
I don't know exactly what you want from your engine, but on a higher output application, the 347 will be significantly down on power above 6,000rpm...and the extra torque down low doesn't really justify it.
That's why I've said it all, plans for a 392 are in motion for me. :D
dude what are you talking about my 342 pulls well past 6000 rpm i shift at 6800 rpm if you set the motor the right way the first time you need to talk to professionals to get proper combo or ask someone that has a good combo for advise,
Building a 331 over a 347 (for the same price) is like building a 2 Car Garage and not a 2 1/2 Car Garage for the same price. Why? I understand being unique, but that's something no one can see. I wanted a 327 stroker (just to be different and it's basically a 331 without the overbore) but since 347s are the same price I really didn't see the point of leaving horsepower on the table.
exactly darkthunder
and to be unique who the f*ck really cares who knows what is inside the engine unless you tell. everyone thinks that i have a 327 now but they will never know what is really inside, build Cubic inch, there is no replacement for displacement! you can builld a very welll mannered 342 or 347 that will kick ass run 10's and drive to and from the track.
I never said they can't turn high rpm...I said they would be down on power in that range compared to a 327/331....and that is from a professional...according to Tom@D.S.S. You'll also be re-ringing a 342+ engine before you are a 327/331. I'm not trying to on the 342/347...hell, my buddy has a carbed 347 in his 'stang that he drives on a daily basis and runs consistent 11.70's off of the convertor.
If you don't intend on turning 6,000rpm on a regular basis, a 342/347 is the better choice...BUT, if you plan on building a wild, high-winding stroker...don't go bigger than a 331
Is this scenario assuming an identical setup except for the stroke?
A 347 CAN be rebuilt. If you're worried about cylinder wall thickness you could go 342 (347 without the overbore)
Not if you feed it enough air and gas.
As far as rod:stroke ratio with a 5.4 rod:
331 = 5.4 / 3.25 = 1.662:1
347 = 5.4 / 3.4 = 1.588:1
For the 5.315 rod:
331 = 5.315/3.25 = 1.635:1
347 = 5.315/3.4 = 1.563:1
How do you have some block left with one and not the other? They are the same bore. And those few HP are
FREE
Looks like Tom from D.S.S. states in this (http://"http://www.musclemustangfastfords.com/projectcars/mmfp_0410_mustang_dss_engine/index.html") article why the 331 is superior to the 347. I say s!
He claims the horrid rod ratio can collapse cylinder walls from the extreme side-loading. At the same crank angle, guess how much more theoretical side-loading the 347 exerts over the 331....
3%.
ZOMG!!!
Certainly you'll get a little more in the real world due to deformation of the piston skirt because the 347's is shorter...but not enough to break friggin' cylinder walls.
Properly installed piston ring support rails will make oil consumption a non-event.
I honestly can't see any reason to run a 331 over a 347 unless you're spraying ginormous amounts of NO2 or running a wicked power adder. A 347 increases your torque over a 331 and brings down the peak hp rpm to decrease stress on everything.
This guy is SOOOOO full of it.
Perhaps if you put the same heads and cam on both and those parts were barely up to the task of feeding a stock bore and stroke 302
Correct!
Oh, almost forgot this:
Gee.....that's funny I know of a car that weighed 2800 LBS
WITH driver and a drag suspension pushed by 557 RWHP from a STOCK BLOCK 302 with a .030" bore and stock stroke. It was in the 10's with 4.10's out back, still in the 10's with 4.56's....
So tell me how that engine in a car with 300 more pounds would be 4-5 tenths faster.
So why build a 347 when you can go to a 351 for less money?
Must be a reason because they are very popular, but I could never figure out why.
TED
Me neither:hick:
331 with a Supercharger or Turbo
347 for a all motor bulid
But if its ture that BadBird car runs a 11.60 1/4 ET you might want to listen to him if you don't want to invest into a power adder of any kind.
Since this high dollar nice supercar does the 1/4mile in 11.9s you might wanna put him to shame at least a little while off a stop light.
http://www.rsportscars.com/eng/cars/ferrari_599gtb.asp
Less hassle - no need to find a new oil pan, accessory brackets, other ancillary items, deal with hood clearance issues. Entire assembly weights less, smaller main journals, lighter internals (mainly the crank), ability to run EDIS...
It isn't so cut and dry and really not that much more expensive to run a 347 versus a 351W. Keep in mind I am assuming one is using the stock hood - a must for me. That necessitates a 5.8L GT-40 lower and those run $300-400 bucks alone.
I think that platitude is all too general.
www.foxtbirdcougarforums.com[/url] is starting to sound like http://www.Corral.net now.
Joking:giggle: :giggle:
My 2 cents is though I still find this an interesting discussion iv been told by a few including my machine shop that this is old news. The 347 crank has been figured out; problems are in the past anything bad you see is either old work still around or some poor just got an old set-up off the dusty shelf.
No matter what they've "figured out", the 347 still has much more piston speed than the 331...for the street with an auto tranny, I'd go with a 342/347, but if you're building a high winding motor, i'd go with a 317 or 331....less friction = more power at higher RPM, funny how some people don't understand that.
OK speaking of piston speed and high winding motors I tried bring this up on corral but subject got dropped. But is this possible and has anyone done it.
Who here knows about the SBC/302 Z28 motor it’s a de-stroked 350 both w/4’bore but w/a 3’crank instead of a 3.5 crank those how know the motor when it was in existence it was an absolute animal but not very street friendly w/is maybe one of the reasons chevy stopped making it but it easily went 10,000 rpm on the street.
So my point is has anyone took a 351 block and de-stocked it w/a 302 crank or even a 331 crank.
If you’re interested this is the tread on corral it’s a 383 vs 408 argument for a guy making a road course car my post is #63 at the end I have a little more detail there. http://www.corral.net/forums/showthread.php?t=962431&highlight=383+408
Yea id love to know what you guys have to say on a 383 against a 408. I'm stuck between the two for the motor i wanna build in my stang. heads are gonna be afr 185s, maybe 205's
The 383 vs. 408 is basically the same arguement as the 331 vs. 347 arguement. When it comes to the 351, 393 is about as big as you'd like to go...yes, guys are building stock block 408's and I've even heard of 427's, but that's a long crank and a lot of piston speed.
By that logic Wouldn't you be better off with a stock stroke 302/306then?:rolleyes:
Either way, go with the 205 heads......
Bottom line.....If you can get the same power out of two motors and one needs to rev 1000 RPM less which way would you go? High RPM kills motors faster.
so 205's it is.
I've heard 408, is not very kind on a street/strip setup, and was told either 383 or 393 was the way to go.
Holy back from the dead thread batman. Lol I made this forever ago, the shop that was going to do it went out of business... and then I sold the T-bird, and bought something with a 347(346 technically) in it.
Good information none the less. Keep up the debate guys!