331 or 347 stroker? pros and cons?

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90stangLX302

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Good ol' Bellaire Ohio

Jun 16, 2004

#1

• Jun 16, 2004

• #1

What are the pros and cons of a stroker kit in the first place? Also what are the differences like the downsides or upsides between the 331 or 347. I already have a block bored .030 over so all i need to do is get the kit and put it in. If it says that they are balanced, then does that mean its ready to just bolt right in and throw a harmonic balancer on?

 

ironheart1

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Mar 13, 2004

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Jun 16, 2004

#2

• Jun 16, 2004

• #2

Stroker kits provide a larger displacement, and thus more horsepower and torque. However, larger stroker kits like the 347 decrease engine component life due to the great deal of piston travel. I have seen 347s that burn oil noticably after 10,000 miles, so you take a risk with a stroke. The lower the stroke, the less you gain but also the less you lose in durability.

I have also heard that stroker kits decrease the safe rev range or the power peak in the engine but I'm not certain about this.

 

K

kystang1889

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Dec 29, 2002

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ky

Jun 16, 2004

#3

• Jun 16, 2004

• #3

ironheart1 said:

Stroker kits provide a larger displacement, and thus more horsepower and torque. However, larger stroker kits like the 347 decrease engine component life due to the great deal of piston travel. I have seen 347s that burn oil noticably after 10,000 miles, so you take a risk with a stroke. The lower the stroke, the less you gain but also the less you lose in durability.

I have also heard that stroker kits decrease the safe rev range or the power peak in the engine but I'm not certain about this.

Click to expand...

what a stroker kit does is takes the best of both worlds the hp of a long rod motor with the tourque of a HIgh comp. motor, what your doing is increasing the stroke which then raises the highth on the piston pin which is bad and is what shortens its life, long rods make lots of power b/c the longer the stroke the more down ward force is made on the power stroke of the motor, with a stroker you also have the tourque.

 

9

90stangLX302

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Jun 16, 2004

#4

• Jun 16, 2004

• #4

How is driveability on a stroker motor, and which cam would be good with my mods

 

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1Quik85GT

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Gadsden,Al

Jun 16, 2004

#5

• Jun 16, 2004

• #5

I just built my 331 and so far I like it I havent ran it yet, because I am waiting to put about 1,000 miles on it... the 331 is still a high reving engine.. I have heard the same about the 347 oiling problems, but the reasoning behind that is the pin is in the oil ring... but i do belive CHP makes a 347 kit that gets around that.. In talking to some racers...the 347 is a good stroker as well as the 331...its just your pick on what you want...

 

ironheart1

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Jun 17, 2004

#6

• Jun 17, 2004

• #6

Stroking to a 306 only adds 4ci of displacement.. Does anyone have any opinions on whether or not this is even worth the money? Would a 306 have a noticeable power advantage over a 302? Well, with a .030 over its a 308, but who's counting

 

Venom4.6

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Jun 17, 2004

#7

• Jun 17, 2004

• #7

ironheart1 said:

Stroking to a 306 only adds 4ci of displacement.. Does anyone have any opinions on whether or not this is even worth the money? Would a 306 have a noticeable power advantage over a 302? Well, with a .030 over its a 308, but who's counting

Click to expand...

A 306 isn't a stroker. It's just bored.

 

Smokedawg

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Jul 6, 2001

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Jun 17, 2004

#8

• Jun 17, 2004

• #8

If its a daily driver, I would freshen it up with a rebuild kit and have it bored .030 and be done with it...If you looking for something to play with every so often, go 347

Besides my oil galley plug falling out..I have had 0 problems with the motor..

-Smoke

 

houstonstangguy

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Jun 17, 2004

#9

• Jun 17, 2004

• #9

i went with the 331 chp kit over their 347. streetability depends on the components you put on/in it. you could get a small cam or a custom and have it very streetable. depends on what you want it to do.

i have the tfs stage 3 and it is very very lopey. plus streetable all depends on the owner/driver. what might be too much for someone, might be perfect for someone else. best way to know is find someone local and feel their car and see what they have. do that until you find a combo you like.

 

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90stangLX302

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Jun 17, 2004

#10

• Jun 17, 2004

• #10

I did some calling around and I think I am goin to go with the CHP 331ci Street Fighter Pro Street kit and have them balance it. It comes with a forged crankshaft and 4340 forged rods and Probe SRS forged flattop pistons giving me a comp. ratio of about 10.35:1. As for the cam, I think I am going with the FMS E303. Any suggestions or other ideas let me know

 

Mustang5L5

That is…until I whipped out my Bissell

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Feb 18, 2001

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Jun 17, 2004

#11

• Jun 17, 2004

• #11

So what are the pros/cons of the 331 vs. 347??

I am planning a motor for my '88 and my engine will either be a 331 or 347. But which to choose? Car would only be a "toy" at this point.

WHat are the characteristics of each? WHich revs higher? Responds better? Which would be better with about 6-8 pounds of boost?

 

houstonstangguy

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Jun 17, 2004

#12

• Jun 17, 2004

• #12

hey mike,

either would be good with boost. just make sure you go low compression with it. i love my 331 street fighter. call chp and get it right from the horses mouth on what would be better for you. i pretty much only drive my coupe 1 or 2 days a week now that I have an avalon to drive to and from my classes which are about 40 miles away. I look forward to driving the coupe to class though and it always keeps a smile on my face! in a few months I plan on putting a wet kit on, just not sure which one yet.

I would recommend chp's girdle for both of you like I did.

 

9

90stangLX302

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Good ol' Bellaire Ohio

Jun 18, 2004

#13

• Jun 18, 2004

• #13

If i am going n/a, would there be a need for a forged crank, or would the cast crank be safe?

 

89CopCoupe

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Feb 17, 2004

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Post Count City

Jun 19, 2004

#14

• Jun 19, 2004

• #14

302 blocks have a 'deck height' of 8.20" (meaning from the center-line of the crank up to the head/piston surface of the block)

302 has a 3.00" total stroke
331 is increasing the total stroke to 3.25"
347 is further increased to 3.40"

When you stroke the 302 block to a 347 you create a situation where the pistons 'compression height' (distance from center line of wrist pin to top of the piston) must be shortened so much that the wrist pin bore intersects with the lower piston ring (oil control ring) ...... oil consumption issue.

To combat this, CHP/DSS use a shorter rod and a taller c.h. piston.

Until you build upwards of 500 flywheel horses it is unnecessary to buy forged parts (unless you prefer piece of mind). The stock block will go before rotating assembly.

Personally I would go with a 331 if you want good longevity. The 347 puts a little more stress on cylinder walls as well.

90LX, you're thinking about the "E" cam, what other parts are you considering?

 

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90stangLX302

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Jun 19, 2004

#15

• Jun 19, 2004

• #15

89CopCoupe said:

90LX, you're thinking about the "E" cam, what other parts are you considering?

Click to expand...

I was just thinking about the 331 kit and that E cam i already have the head intake combo listed in my sig. Do you have any suggestions on a different cam or other parts that i will need.

 

Mustang5L5

That is…until I whipped out my Bissell

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Feb 18, 2001

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#16

• Jun 19, 2004

• #16

For a 331, all you would need is the stroker kit correct? Is it neessary to bore the cylinder walls any?

I'm contemplating whether i should order a 331 short block or use my current 100K mile short block and just buy the 331 kit and build it myself. I'm probably looking for 350HP N/A or maybe about 400HP with some boost. I've built 302's before so i'm not worried about it. I'd rather do it mself but some of the short block kits come with beefier blocks.

Thing is i'm not sure what the limits of the stock block are but i also do not want to go overkill and buy a setup good for 600HP and yet only run slightly more than half of that.

 

9

90stangLX302

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Jun 19, 2004

#17

• Jun 19, 2004

• #17

You will need to bore .030 over for the 331 kit, they also have a 327 kit which is with the stock cylinder bore.

(89CopCoupe) "Until you build upwards of 500 flywheel horses it is unnecessary to buy forged parts (unless you prefer piece of mind). The stock block will go before rotating assembly."

 

Mustang5L5

That is…until I whipped out my Bissell

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Feb 18, 2001

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Jun 19, 2004

#18

• Jun 19, 2004

• #18

90stangLX302 said:

(89CopCoupe) "Until you build upwards of 500 flywheel horses it is unnecessary to buy forged parts (unless you prefer piece of mind). The stock block will go before rotating assembly."

Click to expand...

So what's the limits of the stock block? I'm just wondering if i can build into the stock block or if i should go for something beefier.

Like i said, i'm shooting for 350-400HP

 

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90stangLX302

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Jun 19, 2004

#19

• Jun 19, 2004

• #19

You would probably be fine with the stock block. From what i hear and understand, you are ok untill you get near the 500 mark.

 

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90stangLX302

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Jun 19, 2004

#20

• Jun 19, 2004

• #20

I am still wondering if it is worth it for the power. I can't find estimates anywhere of how much power and torque will be gained, on a stock h/c/i combo or my specific combo. If anyone has some numbers of before and after the stroker kit please share them with me. I read somewhere a guy only got 15 hp out of it. To me 15 hp isn't worth a grand or more.