331 Stroker

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"I even have seen many say a gear ratio of 3.55 will keep your car from turning too many rpm's when cruising at highway speeds so that is why you don't want to consider the next step up which is the 3.73 ratio."

Um, I have had both and 3.55's do spin the engine lower rpm's. Any RPM calculator will tell you that. Not sure what your point is on that "ratio" (pun intended)

"The small amount of truth in it is blown up to represent WAY more of a disadvantage than it REALLY is."

Ok, true.
 
5spd GT said:
Let me say it again...more reasons...because the 331 is different, less aggressive rod ratio, more piston material, and the majority of the time the 331 doesn't have to be "stroker clearanced"...

Yes, it is different. It's different because anyone building a stroker motor would want more power for the same money. I would indeed call someone "different" (and probably some other things as well) that wanted a NA 331 stock blocked motor over a 347 for the uniqueness of it. The only thing unique about the 331 is that it is uniquely slow.

If you are going to put the poster's internals into a 331 and dyno tune it, and then a 347 and dyno tune it, which one gets you down the 1320 first? My money is on the 347.

Adam
 
Pokageek said:
"I even have seen many say a gear ratio of 3.55 will keep your car from turning too many rpm's when cruising at highway speeds so that is why you don't want to consider the next step up which is the 3.73 ratio."

Um, I have had both and 3.55's do spin the engine lower rpm's. Any RPM calculator will tell you that. Not sure what your point is on that "ratio" (pun intended)

"The small amount of truth in it is blown up to represent WAY more of a disadvantage than it REALLY is."

Ok, true.

I think the comparison of 3.55's to 3.73's Shows the Lemming Syndrome in all its Glory.

Before I go any farther here ... I'm not calling you a Lemming :nono:

Lemming is just a word I think perfectly describes how some info with half truths gets passed on and on.

But to show how this kinda thing goes ..........

I'll let you De-Lemmingize the 3.55/3.73 subject by answering this one Q

Keeping ALL things equal but the final gear ratio ......

How much less DO 355's turn at a 60mph cruise than 373's?

I await your or anyone elses answer :D

Grady
 
To add some fuel to the fire, B&B Performance who does A LOT of 5.0 motors was not impressed by the difference between 347's and 331's. He has an in-house dynamometer and hasen't noticed a difference between 331's and 347's. For all the people that say 331's suck, um, won't they make more power than a 302??? Let the guy buy what he wants. It's not your money is it? One of my good friends makes 345rwhp with his 302 running a .545 lift cam and afr 165's.

BACK TO THE TOPIC!!!!

I think you'll make over 330rwhp no problem, a little more if you get a cam that will put those AFR 165's to work!! You should be low 12's no problem!
 
Like said above its all in the combo you want.

If your keeping the H/I/C from your 302 you might as well keep it a 302-306 or maybe...maybe a 327. It would come down to a strong 302-306 or a preaty mild 331/327.

As far as the piston. I called around when looking at getting a 306 or a 331 (the reason I stuck with a 306 is the H/C/I I run now and didnt want to get rid of). The numbers they gave me added up to this

The pistons were the same from the 331 to 306 and 306 longrod. It seemed to me that they decked the blocks that much more to make up for it in order to use the same pistons over a few diff. CID motors. That is why I needed a .120 shorter PR when I only was .064 shorter on mill on the heads.

So the pistons "could" be the exact same as the 331/347 but with a shorter deck hight to bring the pistons to 0 deck...
 
final5-0 said:
I even have seen many say a gear ratio of 3.55 will keep your car from turning too many rpm's when cruising at highway speeds so that is why you don't want to consider the next step up which is the 3.73 ratio.

That is the thing about a lot of info you hear .................

Grady

Right there proves you have NO CLUE what your talking about. You have officially thrown off all we know about mathematics and now the Earth is going to explode. Good Job. :nice:
 
Blk91stang said:
To add some fuel to the fire, B&B Performance who does A LOT of 5.0 motors was not impressed by the difference between 347's and 331's. He has an in-house dynamometer and hasen't noticed a difference between 331's and 347's. For all the people that say 331's suck, um, won't they make more power than a 302??? Let the guy buy what he wants. It's not your money is it? One of my good friends makes 345rwhp with his 302 running a .545 lift cam and afr 165's.

BACK TO THE TOPIC!!!!

I think you'll make over 330rwhp no problem, a little more if you get a cam that will put those AFR 165's to work!! You should be low 12's no problem!

:OT: Can you give me details on your friends combo? That sounds outstanding. How high is he revving that guy? That must be a fun as hell car to street!

Adam
 
Black95GTS said:
Yes, it is different. It's different because anyone building a stroker motor would want more power for the same money. I would indeed call someone "different" (and probably some other things as well) that wanted a NA 331 stock blocked motor over a 347 for the uniqueness of it. The only thing unique about the 331 is that it is uniquely slow.

Lol, your just jealous because there isn't a big difference in power between them. So do you call people that have a 393 instead of a 408 "different"...

I think you missed the point...

Back to the dart board for ya...

So is the 347 so much faster. 16 cubes will kill any other car huh?

So according to Adam's theory and bias, 331's are slow and 347's are fast:rlaugh:

Black95GTS said:
If you are going to put the poster's internals into a 331 and dyno tune it, and then a 347 and dyno tune it, which one gets you down the 1320 first? My money is on the 347.

Yep, mine 2...

What's your point? That it is a bit quicker?

Whoopdeeduu...
 
final5-0 said:
No prob my friend ... I have it handy :banana:

Here you go :)

http://www.allfordmustangs.com/Detailed/608.shtml

Grady

:OT: I know.

I've got 3.90's right now and would rather rev higher on the HWY. Maybe the biggest "internet myth" surrounding the gears is people saying but you gas mileage is gonna suffer bad goin from 3.08's to 3.73's. Not true! Been there done that! (I hear that on the street alot)
 
5spd GT said:
Lol, your just jealous because there isn't a big difference in power between them. So do you call people that have a 393 instead of a 408 "different"...
I think you missed the point...
Back to the dart board for ya...
So is the 347 so much faster. 16 cubes will kill any other car huh?
So according to Adam's theory and bias, 331's are slow and 347's are fast:rlaugh:
Yep, mine 2...
What's your point? That it is a bit quicker?
Whoopdeeduu...

My point is if you already have the internals you are going to use, and you are building a stroker, why wouldn't you build the one that makes the most power? Sideloading of the block is a non-issue with what he's throwing in there. Why go slower when you could go faster?

This isn't a general 331 vs. 347 discussion. The poster has X parts, he's gonna build a stroker... if you're going to build one anyway, you might as well spend the same loot and put more power down.

Well a 347 is only 5 cubes more then a 342. Of course a 331 is only 4 more cubes then a 327. And thats only 21 cubes more then a 306. And thats only 4 more then a 302...

If we continue with that logic, we'd all be riding bicycles.

Adam
 
Blk91stang said:
Right there proves you have NO CLUE what your talking about. You have officially thrown off all we know about mathematics and now the Earth is going to explode. Good Job. :nice:

:rlaugh:

His point was that all things being equal but the gears, 142 rpm at 60 mph is not going to affect the fuel mileage enough to notice. The driving style is what does it. I think some people on here get all stressed out over details sometimes... $.02 :nice:

Scott
 
Blk91stang said:
ok, first prove it makes more power other than saying "more cubes = more power". There's many variables to an engine other than displacement.

Agreed. But back to the original post, there aren't those variables in this situation. He has the parts already. Are you telling me that all else being equal, a 331 will equal a 347 in power output? Say you take the recommended RPM limit of the track heat, which is 6500 I believe. Rev both engines, all else being equal to 6800 or so. I will bet that the 347 betters the 331. I will also bet that the car with the 347 is faster on the track and on the street.

I'm saying, with the parts the poster has, he will make more power in a 347 then in a 331. That's all. I'm not saying a 331 is better/worse in general. In this application, it makes more sense to to go 347.

Adam
 
Blk91stang said:
ok, first prove it makes more power other than saying "more cubes = more power". There's many variables to an engine other than displacement.

I don't feel the need to prove is the most important thing to keep in mind in this discussion.

Lets just present some facts and then see if we can draw a conclusion to see where this goes :shrug:

IMHO, the general topic of interest is how strokers make power and how some peeps think bigger gives you more options than smaller.

That Pro Engine Builder above who said he has seen no power difference between 331 and 347 is really interesting to me. I do not claim in any way to know as much or even more than him

but

I do think I've got reasonable common sense about most things :)

Lets set aside the stroker for a short while and talk about a combo that is more commonly seen on this and other forums that deal mostly with street applications.

One kinda like mine ... a stock oem shortblock h/c/i street combo.

They are a dime a dozen ... are they not :shrug:

Most make 300rwhp give or take a few ... do they not :shrug:

Ain't that about 1rwhp for each cubic inch :shrug:

Now lets go back to the 331/347 srtoker combos and use the same degree of logic as our stock oem example combo and build a stroker with the same objectives in mind.

Why would the typical street combo 347 not make about 16 more rwhp than the 331 if each shortblock was built on an equal basis and the supporting parts were equal :shrug:

Grady
 
Black95GTS said:
Agreed. But back to the original post, there aren't those variables in this situation. He has the parts already. Are you telling me that all else being equal, a 331 will equal a 347 in power output? Say you take the recommended RPM limit of the track heat, which is 6500 I believe. Rev both engines, all else being equal to 6800 or so. I will bet that the 347 betters the 331. I will also bet that the car with the 347 is faster on the track and on the street.

I'm saying, with the parts the poster has, he will make more power in a 347 then in a 331. That's all. I'm not saying a 331 is better/worse in general. In this application, it makes more sense to to go 347.

Adam

Yes, in theory by thinking "more cubes = more power", you are right!!! Only there are other factors that come into play. Like I said before, a VERY reputable shop has dynoed NUMEROUS 331's and 347's with matched combos and never noticed any significant differences in the power output between the two. The fact there the rod angle "is" different on a 347 can contribute to "some" lost power.

No i'm not telling you a 331 has more power than a 347 as I've never said anything like that before. I just stated that no one has FACTS proving one makes more power over the other. This argument will go on forever.

I could care less if someone has a 331 over a 347 or vise versa. They both make kickass power and have the ability to run like raped apes!!!

(I refrain making any more comments about this debate because it's just people arguing their opinions without facts, and that includes myself :bang:)
 
Untuned with the mods listed in my sig below I made 317 rwhp and 355rwtq with only 800 miles on a fresh engine.

As for the 1/4 times, I ran a 12.32 at 111 mph on Mickey T Drag radials and a 12.30 at 110mph on Mickey T ET Drags. Both 60's were in the high 1.5 range. I probably could have gone deeper in the 12's if I had been power shifting but with 176k on the stock T-5 i did not want to chance it and pay a wrecker the 100 mile tow bill back to my house.

I have the tweecer but have yet to get time to mess with it and re-dyno.

More Specs on my combo are:
10.5:1 CR flat top pistons
the heads have been milled to 58cc
Cometic Head gaskets.
My cam is built more towards the nitrous than N/A so that will have an effect on the HP.

Hope this gives you some insight in you quest,
Tommy