331 vs 347

Reply #15 – June 01, 2006, 11:35:13 AM

Quote from: badbird

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,

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

331 vs 347

Reply #16 – October 31, 2007, 06:45:04 PM

Quote from: Sick88Tbird;86782

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.

Is this scenario assuming an identical setup except for the stroke?

331 vs 347

Reply #17 – October 31, 2007, 07:20:56 PM

A 347 CAN be rebuilt. If you're worried about cylinder wall thickness you could go 342 (347 without the overbore)

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I said they would be down on power in that range compared to a 327/331

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

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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.

How do you have some block left with one and not the other? They are the same bore. And those few HP are FREE

331 vs 347

Reply #18 – November 01, 2007, 02:17:04 PM

Looks like Tom from D.S.S. states in this 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.

331 vs 347

Reply #19 – November 01, 2007, 02:23:36 PM

Quote from: JeremyB

Looks like Tom from D.S.S. states in this article why the 331 is superior to the 347. I say s!

Quote from: From that article

A 331 is almost 40 hp better at 6,000 rpm than a 347

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

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Properly installed piston ring support rails will make oil consumption a non-event.

Correct!

Oh, almost forgot this:

Quote from: That article......AGAIN!!!!!

With zero retard and the same boost, the Mustang laid down 512 hp at 5,800 rpm and 500 lb-ft of torque at 4,700 rpm. In a 3,100-pound car with a good suspension, that's 9-second power folks.

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.

331 vs 347

Reply #20 – November 01, 2007, 07:35:14 PM

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

331 vs 347

Reply #21 – November 01, 2007, 11:33:37 PM

Me neither:hick:

331 vs 347

Reply #22 – November 02, 2007, 03:33:29 AM

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

331 vs 347

Reply #23 – November 02, 2007, 11:07:04 AM

Quote from: Cad-T-Bird 500;185828

So why build a 347 when you can go to a 351 for less money?

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.

Quote from: Carpimp 1987

331 with a Supercharger or Turbo

347 for a all motor bulid

I think that platitude is all too general.

331 vs 347

Reply #24 – November 02, 2007, 07:22:46 PM

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.

331 vs 347

Reply #25 – November 03, 2007, 05:23:30 PM

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.

331 vs 347

Reply #26 – November 03, 2007, 06:43:00 PM

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

331 vs 347

Reply #27 – November 03, 2007, 06:44:59 PM

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

331 vs 347

Reply #28 – November 03, 2007, 06:52:12 PM

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.

331 vs 347

Reply #29 – November 03, 2007, 07:31:11 PM

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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.

By that logic Wouldn't you be better off with a stock stroke 302/306then?:rolleyes:

Quote

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

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.