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Author
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Topic: 351W vs. 347
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Curt
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Member # 6254
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posted
 
 
It seems like the 347 is hella expensive! I know its stronger and all but why not go with a Windsor (yes I know the 302 is a windsor too) then you have 351 cubes to start with, sure its a little wider (or is it taller?) but you can't beat $90 for 49 more cubes!
Obviously the lower intake selection will be limited and smog could be hard, and I doubt its a roller but don't they make 418 kits for the 351?
It seems like for the price of a 347 you could have a bada** 351!
What do y'all think?
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'90 GT
'94 Toyota 4wd "It have problem"
'56 F100 5.8 AFR185's Vortech SC S-trim
Posts: 866 | From: Monterey/Rocklin | Registered: Nov 2005
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88DroptopGT
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Member # 2535
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posted
351 Windsors are beefier but you have to buy conversion parts.
Smog is not a big deal since most smog techs don't notice the taller deck of a 351 unless they check engine casting #'s.
Everyone makes 408ci stroker kits for Windsors. Shoot on dart block you can stroke all the way to 454ci!
Building any engine is expensive, but you gotta "pay to play".
Personally I would go with a 351. I'm selling a machined block as well. ![[Wink]](wink.gif)
Posts: 3978 | From: 707 | Registered: Mar 2003
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93PONY
Mr. Valve Events
Member # 60
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posted
Neither is stronger then the other rotating assembly wise. You can get good quality forged components for either motor.
The 351 block is stronger then the 302. However either Dart 302 or 351 will handle far more then we'll ever be able to throw at it.
The 302 has an 8.2" deck height, the 351 has a 9.5" deck height. The rods on an 8.2" deck are shorter & therefore lighter then a 9.5" deck rod. The lighter the rod, the faster the motor will rev. The faster it revs.....the faster it gets through it's powerband. Also, the shorter the rod, the stronger it is....same with pushrods....which are also longer on a 351 vs 302.
Fast reving motors is something that most don't consider when looking at dyno graphs. There's more to it then simply peak power. How fast a motor revs is KEY in how fast the car will be.
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www.advancedenginedevelopment.com
SCT dealer
Dynotuning
(916)715-7569
Posts: 4265 | From: Fair Oaks, CA | Registered: Nov 2000
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CDT
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Member # 5004
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posted
they both cost about the same to build, if built to the same levels. the 351w block is stronger, but it seems as he 302 blocks only have trouble on boost.
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Custom Dyno Tuning
510.331.0608
Home of Flat Fee Tuning For All Cars, Trucks and SUV's, EFI & Carb, SCT, AFR, Dynatech, STS Turbos, N2O Refills
Posts: 1053 | From: Hayward | Registered: Nov 2004
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CobramanPhil
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Member # 2170
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posted
quote:
Originally posted by CDT:
they both cost about the same to build, if built to the same levels. the 351w block is stronger, but it seems as he 302 blocks only have trouble on boost.
Probably due to the lack of sealing surfaces between the piston walls...ughhhh another gasket failure ![[Frown]](frown.gif)
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2013 Shelby GT500
2011 Porsche 911 TurboS/AWD
2014 GSXR750
2002 GSXR750 Track Beater Bike
2016 Explorer Unlimted
Posts: 1016 | From: California, Bay Area | Registered: Dec 2002
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Joooestang66
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Member # 2828
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posted
In the long run a 347 will wear out alot faster than a 351.
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"Don't Drive Faster Than your Guardian Angel Can Fly..... Well My Guardian Angel Can Fly Pretty Fuc*ing Fast!!!"
Posts: 581 | From: Elk Grove | Registered: May 2003
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CDT
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Member # 5004
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posted
quote:
Originally posted by CobramanPhil:
quote:
Originally posted by CDT:
they both cost about the same to build, if built to the same levels. the 351w block is stronger, but it seems as he 302 blocks only have trouble on boost.
Probably due to the lack of sealing surfaces between the piston walls...ughhhh another gasket failure
I was talking about block failures
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Custom Dyno Tuning
510.331.0608
Home of Flat Fee Tuning For All Cars, Trucks and SUV's, EFI & Carb, SCT, AFR, Dynatech, STS Turbos, N2O Refills
Posts: 1053 | From: Hayward | Registered: Nov 2004
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CDT
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Member # 5004
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posted
quote:
Originally posted by Joooestang66:
In the long run a 347 will wear out alot faster than a 351.
thats really not true
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Custom Dyno Tuning
510.331.0608
Home of Flat Fee Tuning For All Cars, Trucks and SUV's, EFI & Carb, SCT, AFR, Dynatech, STS Turbos, N2O Refills
Posts: 1053 | From: Hayward | Registered: Nov 2004
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2stangs69-91
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Member # 1951
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posted
hmmm so why do the fastest prostock cars IHRA run bigger motors if smaller faster revving ones would be the ticket
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69 Mustang on hold
1991 LX hatch getting a make over
1994 F150 4X4 351
2006 Yamaha V-max 1200 Modded
Posts: 3711 | From: Redding | Registered: Oct 2002
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SPEC -Fabrication
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Member # 4980
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posted
quote:
Originally posted by Curt:
It seems like the 347 is hella expensive! I know its stronger and all but why not go with a Windsor (yes I know the 302 is a windsor too) then you have 351 cubes to start with, sure its a little wider (or is it taller?) but you can't beat $90 for 49 more cubes!
Obviously the lower intake selection will be limited and smog could be hard, and I doubt its a roller but don't they make 418 kits for the 351?
It seems like for the price of a 347 you could have a bada** 351!
What do y'all think?
I would take in the note that the 347 is still haveing Rod issues, 331 is much more safer, My friend road races a 331 ony after going threw 2 347's , Rods were snapped in both due to the stroke and High revs for periods of time ![[Eek!]](eek.gif)
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1999 Saleen#124
1997 Tahoe
2006 ZX636R
CWS certified welder
Posts: 1321 | From: drinkin BEER! | Registered: Oct 2004
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v-town coupe
fordologist
Member # 2771
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posted
dman this could go back and forth all day i prefer 347 due to the fact every thing i have is already set u for a 302 and less stuff to buy for a conversion and i also dont have the hood clearence on my car to accomidate a taller deck height cause once u start building a pretty tough motor you will need and intake to back it up! i d like the fact that a 347 will rev quicker but hey any motor will with the right parts and dont let the 347 scare u away they have come a long way with diffrent rod lenghts and what not to kep the wrist pin out of oil control ring but its all prefrence jus my .02
Posts: 4597 | From: the V-town | Registered: May 2003
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JoeT
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Member # 298
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posted
don't forget to budget for:
drop motor mounts, swap headers, 351w pan, different timing cover, different accessory brackets, different flywheel, the already mentioned different lower intake, the motor is both wider and taller (not all 351s are 9.5", some are 9.2", watch out when ordering a rotating assembly if you have an early windsor block) and there's probably a few odds and ends which may come into play like possibly needing a different hood depending on your intake/carb/motor mount choice.
all told the swap parts for a 351 negate any real $ savings over going with 'just' a 347
Then again, IMHO we shouldn't be comparing a 351 vs a 347.... I would say compare a 408/427 vs a 347.
Don't forget the ~ 60# weight penalty the 351w block carries (comparing production blocks).
Also, if you're considering a 351w, for many of the same reasons you should also consider a 460 (or a 454 )
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1984 Ford Tempo AOD--- RIP
Posts: 6785 | From: San Jose | Registered: Jun 2001
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93PONY
Mr. Valve Events
Member # 60
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posted
quote:
Originally posted by 2stangs69-91:
hmmm so why do the fastest prostock cars IHRA run bigger motors if smaller faster revving ones would be the ticket
As we all know, there is no replacement for displacement.....
I don't see you racing a Honda.
Why do they use aluminum rods?
Apples to Oranges.....but you know that. You just like bust'n my balls from time to time. ![[patriot]](graemlins/patriot.gif)
There are no real issues with the current line of 347's.
The oiling/longevity issues were due to the oil ring & pin locations. This was 'fixed' with a support rail under the oil rings. Even better is the 5.315 rod with a 331 piston. No more issues.... There is no reason why a properly built 347 will not last YEARS racing & 100000+ miles if taken care of.
[ December 20, 2005, 10:57 PM: Message edited by: 93PONY ]
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www.advancedenginedevelopment.com
SCT dealer
Dynotuning
(916)715-7569
Posts: 4265 | From: Fair Oaks, CA | Registered: Nov 2000
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stoauto
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Member # 2803
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posted
quote:
Originally posted by SPEC -Fabrication:
quote:
Originally posted by Curt:
It seems like the 347 is hella expensive! I know its stronger and all but why not go with a Windsor (yes I know the 302 is a windsor too) then you have 351 cubes to start with, sure its a little wider (or is it taller?) but you can't beat $90 for 49 more cubes!
Obviously the lower intake selection will be limited and smog could be hard, and I doubt its a roller but don't they make 418 kits for the 351?
It seems like for the price of a 347 you could have a bada** 351!
What do y'all think?
I would take in the note that the 347 is still haveing Rod issues, 331 is much more safer, My friend road races a 331 ony after going threw 2 347's , Rods were snapped in both due to the stroke and High revs for periods of time
ehh, sounds like he needs a new engine builder.
Posts: 1054 | Registered: May 2003
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jaybquick
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Member # 4286
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posted
quote:
Originally posted by JoeT:
don't forget to budget for:
drop motor mounts, swap headers, 351w pan, different timing cover, different accessory brackets, different flywheel, the already mentioned different lower intake, the motor is both wider and taller (not all 351s are 9.5", some are 9.2", watch out when ordering a rotating assembly if you have an early windsor block) and there's probably a few odds and ends which may come into play like possibly needing a different hood depending on your intake/carb/motor mount choice.
all told the swap parts for a 351 negate any real $ savings over going with 'just' a 347
Then again, IMHO we shouldn't be comparing a 351 vs a 347.... I would say compare a 408/427 vs a 347.
Don't forget the ~ 60# weight penalty the 351w block carries (comparing production blocks).
Also, if you're considering a 351w, for many of the same reasons you should also consider a 460 (or a 454 )
you need a 351 specific distributor too. Also if you already have heads you need to make sure they can handle a 1/2 bolt that the 351w uses. The 302 uses a 7/16 bolt for the heads.
I drive my 347 everywhere, it doesn't eat any more oil than any other performance motor I have. It passes CA smog with a .600 lift cam in it.
I wouldn't go 351w unless you were going to stroke it. It is just really bulky internally and externally compared to a 347 or 331.
Heck if you want the 331 rod to stroke ratio you ca get a dart block, bore it out to 4.125 and have right around 347 cubic inches and the hug bore to rev the crap out of it.
The other question is, how will it be used and what kind of quarter mile performance are you shooting for.
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91 Mustang GT ET: 11.92@115
66 Mustang ET: 11.43@119
01 Audi S4 ET: 10.8@131
05 Audi S4 ET: 11.9@116
08 Audi S5 ET: 11.9@118
Posts: 416 | From: Lathrop | Registered: Mar 2004
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CobramanPhil
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Member # 2170
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posted
quote:
Originally posted by CDT:
quote:
Originally posted by CobramanPhil:
quote:
Originally posted by CDT:
they both cost about the same to build, if built to the same levels. the 351w block is stronger, but it seems as he 302 blocks only have trouble on boost.
Probably due to the lack of sealing surfaces between the piston walls...ughhhh another gasket failure
I was talking about block failures
After a gasket goes south during a run..guess what goes next if you don't immediately shut off the car...KABOOM! A gasket going is sort of a prelude to a eventual block failure...sort of like playing with fire if you think about it ![[Big Grin]](biggrin.gif)
Posts: 1016 | From: California, Bay Area | Registered: Dec 2002
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Curt
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Member # 6254
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posted
how much cheaper are the 331's?
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'90 GT
'94 Toyota 4wd "It have problem"
'56 F100 5.8 AFR185's Vortech SC S-trim
Posts: 866 | From: Monterey/Rocklin | Registered: Nov 2005
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Apexmotorsports
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Member # 5307
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posted
331's are sometimes more expensive... I imagine because there is less demand for them than 347s.
For a 351 you have to remember also that the engine will sit higher and you will need to get a new hood and intake. 351's are great for massive TQ but they are heavier and taller than a 347 or 302 based stroker engine. Installing a 351 will also add to the problem if the Mustang being too heavy in the front... you don't want any more weight in the front if you can help it.
Posts: 957 | Registered: Feb 2005
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