331 vs. 347 Stroker
 

Which is the best stroker kit to go with. I want to keep my engine NA in the future so which is the best choice?

if your staying n/a i would definately go 347.

How long do you want it to last? What kind of use will it see? How much are you planning on spending?

Take care,
~Chris

347 ...if your going NA get as many cubes out of it as you can. You plan on staying under the stock rev-limit?

i disagree, I did alot of research before deciding on what to do with my motor, and a 347 will make for a very poor daily driver. The rod/stroke ratio as well as thinner cylinder walls make for a less reliable engine for a daily driver. On the other hand, the 331 was has a superior rod/stroke ratio with regards to strength. Also, in 347 pistons, the oil ring intersects the wrist pin, which can cause compression problems as well as instabillity. Sacrifice the 16 cubes and go with the 331, it will last much longer.

actually the newer 347 kits have changed the configuration of the pistons and rods and have very liveable rod/ stroke ratios and chp i know has a redesigned piston that alleviates the wrist pin and oil ring intersection they have basically made the 347 just as reliable as the smaller strokers but up until recently the afforementioned problems were quite common but through research and advanced technology the aftermarket has seen fit to improve stroker kits and has greatly advanced their reliability.

Not meant as a flame
 

this is not meant as a flame but did you know most mod motors have the same exact design you just mentioned about the oil rings.

Now does that mean the mod motor is a great engine.......not yet not until they put it in a lighter car with proper gears.

As someone said there are new kits out there with the offset piston ring from CHP they stick out the most,but Lunati makes a 349 kit for a daily driver,so what does that mean now? Who knows.

I will leave you with this there is no replacement for displacement except for maybe a turbo. :)

I did a lot of research and talked to a lot of people before making the choice to build a 331. The 347 simpily didn't fit what I wanted to do with the car, which will be my daily driver and see the track a few times. This motor has to last me a long time and I won't have money to keep rebuilding it. I've head of too many cases that after 10,000 347's started burning oil. My Dad is also an engine builder and helped me make this decision. The 347 is still a great motor, like PKRWUD said, it all depends on what you want to do with your car.

argue all you want but you can't argue physics. 347 pistons have a shorter skirt which plain and simple means less stabillity. I have seen CHP's offset design, and it may work, but you certainly pay for it. The 331 is the better all around choice.

I've learned not to argue with anyone on a message forum, it's all a matter of opinion and preference (some experience helps too:D)...

I stated 347 for the reasons that have already been addressed (CHP)... however, I've had a bare R302 block that I've been wanting to turn into a 331 high-winder since '99 ($$$). I know about rod-stroke ratios... I run a long rod 306 (5.400" rods, 1.8:1)

All you can do is present your case and support it with facts... without getting ugly :D ...and let the person decide for themselves, I never woulda thought the 331 would have become the fad the 347 used to be a few years ago. I thought I was really on to something when I planned for the 331, now everyone wants to run one. I personally prefer the 331, but won't argue with the guy who says the 347 is better...

There is, in fact... no replacement for displacement! ...other than power adders ;)

Good Points Ultra
 

Very well put Ultraflo,
usually I try to stay away from post like this 331 vs 347,TFS TW vs AFR185 because I know where they end up going,right into a pissing contest about what I seen where,and who built it. :)

I think I have a happy medium here,if you want a302 based block race motor go for a 347,the extra throw of the longer rods will help to get it out of the hole,331 for reliability and a few extra revs on the top end of the track,now before someone says well a 331 can do that yes it can no doubt.

Personally speaking,I think if you get it put together properly,there is nothing to worry about with either,when you get off into junk parts and shade tree mechanics is when you run into problems. Ronnie Crawford is the father of the 347(at least he made it fashionable back in 92) and there are guys still out there with his 347's and 100k miles so it is all a crap shoot anyway.

Re: Good Points Ultra
 

Thank you sir... :)

I like, and totally agree with the point you made about assembly and machine work, along with quality components... which most people tend to overlook or even take into consideration. Properly built and tuned, either will make good, reliable HP numbers...

More cubes = more HP/TQ potential

But what if you had a bottle of compressed air, and a leaf blower? Huh Wally?

;)

Take care,
~Chris

...don't forget about the hair dryers!!! ;)

My 'bottle of compressed air' allows me to spank-up on some the N.A. BBC's I come across every time I go to the dragstrip...

Help me understand here, because this winter I'm building a stroker of some kind. Got a 392 hot on the brain at the moment. Anyway, I was under the impression that the cubes were calculated according to stroke length. If I bore a 302 .030" over, isn't the amount of cubes determined by the crank? And if you have to bore more for a 347, how much are we talking about.... .035"-.038"?? A stock 302 block should be good for at least a .050" bore.

In all reality, how many people build strokers to drive to work anyway? If a 331 were to make it 50k miles, an equally well built 347 should go for at least 45k miles shouldn't it. If you're using all the right parts, I don't see how it would make a noticable difference at all.

I believe that a 347 rod/stroke ratio is much better than most any of the big blocks were from the factory. I think it's even better than several of the brand M and brand G small block ratios. I've got a book that lists the ratios here somewhere but haven't found it yet. If I can find it in the next week or so, I'll post some of them on here for everybody's general information.

Sorry about all that babble. All I was really interested in was the necessary amount of overbore. :)

my point was that 4.000 bores will have more cylinder wall than 4.030 bores. That's all. Can't dispute facts

If you want it to last more than 50K miles get a 331

I'd have to concur with that opinion.

While it is true that there is no replacement for displacement, there are other ways of getting it. You're talking 16 cubic inches. That's less than one pound of boost. Get a small blower and a 331, and be happy for a few more years.

Remember, ALL a blower does is increase your displacement (without cutting any metal!).

Take care,
~Chris

SlowGT:

The math goes something like this for your stock 5.0 engine:

4.00 bore x 3.00 stroke x 3.141592654 (Pi) x 8 = 301.59 or 302

My 331 goes like this:

4.06 (which is a .030" overbore) x 3.25 x 3.1415 x 8 = 331.62 or 331

And the 347 kit:

4.06 x 3.40 x 3.1415 x 8 = 346.93 or 347

I personnally like the 331 kit for my application - which includes a ProCharger in the near future. Makes for a well mannered street car that can open up a can of whooop-arse by just taking the rpms up a little. :D

E

Damn. For 20 years now, I have always squared the bore, times .7853982 (easy to remember, used to be my best friends phone number), times the stroke, times 8. Thanks for the tip.

One question: What block are you starting with?