Which is Better 331 or 347

[Modular2v]

My reason is that a 347 pushes the stroke just about to it's limits, whereas a 331, although not a huge difference, is maybe a little safer but i can't say i really have anything to go on there. I said a 331 for boost because whatever cubes are missing when compared to a 347 will easily be made up for with the power adder. Then like i said before, if i were going strictly all motor i'd want all the cubes i could create. In a perfect world if i were going all motor i'd have a Manowar block and 426ci from a long stroke 302-based block. Their stock height 302 Manowar can still handle 370ci.

ditto

 

[ricky50]

No replacement for displacement........

 

[85_SS_302_Coupe]

No replacement for displacement........

Take two identically cubed engines and add boost on one and run the other naturally aspirated and tell me which is faster.



Yeah yeah i know, take the same engine and add more cubes and blah blah, i just think that statement is loosing it's strength over the years. It's definately true but i think it's getting watered down.

 

[Deleted member 87397]

It used to be that nobody made a good piston for a 347 and the wrist pin always crossed into the oil ring and that gave 347s a bad rep on burning oil. Now there's a few out there who make good pistons that get around this. Personally if i were going for boost, i'd go with a 331, but all motor i'd be going for the most cubes possible.

Why would a 331 be better for boost as opposed to 347? Is is just becuase you don't need the extra cubes to make gobs of power or are there other reasons?

 

[Deleted member 87397]

Oops. Ignore my post above found the answer.

 

[blkcobra50]

I went 331...but would have gone boosted 331 off the bat if money grew on trees.

 

[ricky50]

Take two identically cubed engines and add boost on one and run the other naturally aspirated and tell me which is faster.



Yeah yeah i know, take the same engine and add more cubes and blah blah, i just think that statement is loosing it's strength over the years. It's definately true but i think it's getting watered down.

I believe we are talking na engines not boosting of any kind.

Obviously boosting one and not the the other changes things, na 331 versus na 347 is what i am talking about.

We could go on about this but i think you get the point.

 

[5spd GT]

Here is the facts:

A 347 has a steeper rod ratio.

A 331 has more piston material.

With the oil pin in the ring, it does cause for a quicker rate at which oil will seep past the rings into the combustion chamber.

If you go 347, go with the 5.135" rod with a shorter compression height piston to match. Keep the oil pin out of the ringland.

Yes, Chevrolet engines have been doing it for years...many years ago. You also don't see the frequency of 150-250,000 miles out of those engines either.

Yes, the "pin" can be made in the engine...but is it ideal. Absolutley not.

Believe it or not, there is a pretty accurate formula for how much sideloading is given out in force on the sidewalls.

 

[R2D2]

Here is the facts:

A 347 has a steeper rod ratio.

A 331 has more piston material.

With the oil pin in the ring, it does cause for a quicker rate at which oil will seep past the rings into the combustion chamber.

If you go 347, go with the 5.135" rod with a shorter compression height piston to match. Keep the oil pin out of the ringland.

Yes, Chevrolet engines have been doing it for years...many years ago. You also don't see the frequency of 150-250,000 miles out of those engines either.

Yes, the "pin" can be made in the engine...but is it ideal. Absolutley not.

Believe it or not, there is a pretty accurate formula for how much sideloading is given out in force on the sidewalls.

hey how many 331's and 347's have you built?

 

[85_SS_302_Coupe]

hey how many 331's and 347's have you built?

I'm not starting a fight here but do you really think a person has to actually do something to know the facts? I mean...i know a lot more about cars than i've actually done, but does that mean i really don't know anything? Knowledge and ability don't always go hand in hand with finances. I use myself as an example because i can't speak for everyone else. Experience is more valuable than book smarts but knowledge is knowledge.

 

[5spd GT]

hey how many 331's and 347's have you built?

Lol, what does that matter...facts are facts.

You just don't like the fact that a little 331 hangs with those 347's eh

How many houses have you built? Never-the-less you probably know it needs a good foundation to last right?

How many on this site have actually "micrometered" and built the bottomend of a 331 or 347 or any engine for that matter...

I rest my case...it is more "talking" than me...

Bigger engine means bigger ego I guess.

 

[R2D2]

Lol, what does that matter...facts are facts.

You just don't like the fact that a little 331 hangs with those 347's eh

How many houses have you built? Never-the-less you probably know it needs a good foundation to last right?

How many on this site have actually "micrometered" and built the bottomend of a 331 or 347 or any engine for that matter...

I rest my case...it is more "talking" than me...

Bigger engine means bigger ego I guess.

exactly another internet engine builder. Still banned from corral for your crap advice?

 

[Grn92LX]

 

[5spd GT]

Actually I got a letter from the admin., he said that it was because I was causing a stink with a few, so they had to let me go, I told them "that's cool and I understand"...I still lurk on there...here pretty soon it won't be hard to spot me

It wasn't the advice that got me by the way, I never said anything "untrue"...that what was so great about it, but we had a lot of people try to turn the tables...and it ended up flipping over on them I loved every second of it...

 

[Georgie]

dont u have to bore for a 347??...the 331 is just stroked...not bored

im going turbo so i want as much wall thickness as possible...alltho its gonna be a dart

 

[R2D2]

dont u have to bore for a 347??...the 331 is just stroked...not bored

im going turbo so i want as much wall thickness as possible...alltho its gonna be a dart

wrong the 347 and 331 are both 4.030 bore

 

[sunil6784]

I'm building a 331...

Not because of oil consumption and all that. I just want to keep boost options open in the future without having to get a new block. Correct me if I'm wrong, but a supercharged h/c/i 331 will put the block at its limit. Whereas a supercharged h/c/i 347 puts it above 500 or so hp ?

 

[5spd GT]

I'm building a 331...

Not because of oil consumption and all that. I just want to keep boost options open in the future without having to get a new block. Correct me if I'm wrong, but a supercharged h/c/i 331 will put the block at its limit. Whereas a supercharged h/c/i 347 puts it above 500 or so hp ?

Actually the 347 will put the block even closer to running extinction.

A 331 has a less "powerful" sidewall load to the cylinder walls, and the piston has more material to it, which is good to help prevent a 'detonating' spark from ending the piston or engine.

Georgie - A 327 and 342 have the same bore as a 302 but with different stroked crankshafts.

331's and 347's are bored over .030 to acheive those extra cubes.

The 327/331 has a 3.25" stroke and the 342/347 has a 3.4" stroke.

Stroke gives you more cubes than the boring.

I always here people saying in my racing sessions or 'car talk'..."but that engine is bored..." I usually chuckle, or won't say anything...and just beat them. Well "mine wasn't bored" - after the race. I must have got lucky

 

[retro50]

I built a 331 based engine for the fact of no pin in the oil rings, less piston rock in the bottom of the bores. Less piston speed. With a 3.250" stroke the piston doesn't come out the bottom of the bore as far as a 3.400" stroke. This is my opinion. I'm sure someone else will have a different opinion.

 

[Georgie]

is 4.030 the stock bore??