347 or 351w??

[johnny_munyak]

I have been trying to decide what would be a better motor choice for my 95 GT. The current engine is in fine running condition and does not need a rebuild currently, so this whole process is to get a determination on what to do in the future.

I have a good doner 351W roller engine that is running happily in 95’ Ford F150, but was purchased solely for this future purpose. The problem is, the cost factor of getting the 351 w into the car may overshadow the benefit?

The 351 w will require different headers, intake, most likely hood to look after clearance issues, but will benefit from a beefier block with capabilities of going up to a 427 cu in if ever desired.

Now a 347 will achieve 400+hp power levels, be torquey and fun to drive but there is concerns with durability and reliability of the stock bottom end and stock engine block handling that power rating as it is reaching the limits of the factory castings.

I realize that a lot of the extra cost of putting the 351w roller into the car would be similar to what it would cost to get a 347 in the car since the currenty heads, cam, intake on the 302 in the car would not serve well on a 347 or a 351/351 stroker configuration, so that point may be moot.

The upside to the 351 is that it has a stout enough stock crank for most street applications (and this is the primary useage) and the block is also strong enough to eclipse 450 HP ratings.

I’m looking for comments from both parties to determine what they encountered in regards to cost of building/installing either engine.

HCI – both engines will require a larger cam, head, intake setup. Heads may interchange, but may not be sufficient for a big bore unless your heads were way oversized to begin with on the 302. I’m told my Thumper ported GT 40 with larger valves still won’t flow enough for a 347 or 351, let alone a larger cu in stroker.

Intake is not interchangeable with the 351 as the 302 is not wide enough. With a 347, I may get away with my ported lower and a cobra upper which could save a few bucks?

Hood will be an unavoidable cost since there isn’t too many EFI setups on a 351 that will fit under the stock sn95 hood. A GT 40 5.8 intake may help, but for what they are worth on the used market, not financially feasible, so you WILL need a hood. How large will be determined by what intake you end up with??

Headers – long tubes are available for the swap, but very expensive. 347 headers are abundant and easily accessible and cheap. Long tubes shouldn’t be as difficult to acquire or install either.

Both will need a chip to tune and most likely larger injectors than my current 24lb ers. Stock 70 mm MAF and 65mm throttlebody should work fine??

Flywheels and balancers are also not interchangeable so money will need to be spend there as well, whereas a 347 would not need it.

I guess it boils down to useage, desireable power level, and practicality. Obviously the 347 will be the easiest to install since it is basically a punched 302. The 351 will have issues and tribulations, but can fit…but is there any use putting in a 351 if a 347 will have very similar power/torque numbers? If your going through all the trouble of installing a 351, it may as well be a 393 or 408…….but then you have pretty much defeated the purpose of daily driven/street car??

Any thoughts/ideas are welcomed…

 

[BlackVert]

as far as a daily driver, a 347 is probably not that much more desirable (from a daily drivability standpoint) than a similarly powered 351.

actually, one could argue that a 351 could be more mild mannered than a similarly powered 347 simply because of the way the same cam is less radical on a larger engine than it is on a smaller engine

if you decide to keep the 351 bottom end as it is, then you are also looking at the savings of not having to by the crank/rods/pistons that you would be necessary for a 347

and fwiw, i have my 410 under my 96-98 cobra hood. but i also have an AJE k-member that is said to drop the motor about 3/4". i hear that there are also drop motor mounts that also can be used to drop the motor some, but don't have any more details about them

at the end of the day, a 302 based solution will have fewer headaches, while a 351 based solution will give you more growing room in the long term.

 

[Pokageek]

I wanted more block strength and c.i. for the expense. 351 is the way to go.

 

[final5-0]

I have a good doner 351W roller engine that is running happily in 95’ Ford F150, but was purchased solely for this future purpose. The problem is, the cost factor of getting the 351 w into the car may overshadow the benefit?

Yes ... Any expense you lay out to make the Windsor fit could be money
spent on the 347 which of course ... fits no differently than the 5.0

The 351 w will require different headers, intake, most likely hood to look after clearance issues, but will benefit from a beefier block with capabilities of going up to a 427 cu in if ever desired.

Now a 347 will achieve 400+hp power levels, be torquey and fun to drive but there is concerns with durability and reliability of the stock bottom end and stock engine block handling that power rating as it is reaching the limits of the factory castings.

I realize that a lot of the extra cost of putting the 351w roller into the car would be similar to what it would cost to get a 347 in the car since the currenty heads, cam, intake on the 302 in the car would not serve well on a 347 or a 351/351 stroker configuration, so that point may be moot.

Honestly ... If talking NA ... 400 to 450 rwhp is gonna be safe and a pretty
stout street car

I'd not be concerned one little bit with the OEM 5.0 short block

Sure ... If you wanted to do a power adder then I'd be wanting something
more capable than the OEM 5.0 short block

You're gonna have to go to parts capable of supporting 350 cubes so
the headers, intake, etc will be too little anyway

The upside to the 351 is that it has a stout enough stock crank for most street applications (and this is the primary useage) and the block is also strong enough to eclipse 450 HP ratings.

Only You Can Decide ...............

If you wanna go beyond 450 rwhp then the OEM 5.0 short block
just ain't gonna cut the mustard

I’m looking for comments from both parties to determine what they encountered in regards to cost of building/installing either engine.

HCI – both engines will require a larger cam, head, intake setup. Heads may interchange, but may not be sufficient for a big bore unless your heads were way oversized to begin with on the 302. I’m told my Thumper ported GT 40 with larger valves still won’t flow enough for a 347 or 351, let alone a larger cu in stroker.

Intake is not interchangeable with the 351 as the 302 is not wide enough. With a 347, I may get away with my ported lower and a cobra upper which could save a few bucks?

Hood will be an unavoidable cost since there isn’t too many EFI setups on a 351 that will fit under the stock sn95 hood. A GT 40 5.8 intake may help, but for what they are worth on the used market, not financially feasible, so you WILL need a hood. How large will be determined by what intake you end up with??

Headers – long tubes are available for the swap, but very expensive. 347 headers are abundant and easily accessible and cheap. Long tubes shouldn’t be as difficult to acquire or install either.

Both will need a chip to tune and most likely larger injectors than my current 24lb ers. Stock 70 mm MAF and 65mm throttlebody should work fine??

Flywheels and balancers are also not interchangeable so money will need to be spend there as well, whereas a 347 would not need it.

I guess it boils down to useage, desireable power level, and practicality. Obviously the 347 will be the easiest to install since it is basically a punched 302. The 351 will have issues and tribulations, but can fit…but is there any use putting in a 351 if a 347 will have very similar power/torque numbers? If your going through all the trouble of installing a 351, it may as well be a 393 or 408…….but then you have pretty much defeated the purpose of daily driven/street car??

Any thoughts/ideas are welcomed…

The OEM meter is gonna be too little .........
You'll move more air than it can deal with ... end of discussion

I don't care what you do to a pair of E7's
They be too tiny for 350 cubes

Same kinda deal for that OEM Cobra intake

Yes ... They will bolt on a 347 but they will choke it down :Word:

24 lb inj's are too small

You can always sell off the 302 parts

I'd wanna see the cost breakdown between
1) Vortech for the OEM 5.0
2) OEM 5.0 stroked to 347
3) Windsor stroked to ???

I know you did not ask about #1 but it is a way to get to 400+ power
without haveing to go to a Windsor and you could even do it with
the motor you now got

Grady

 

[Pokageek]

All true. If you stroke that windsor, the low end power will own the 347 N.A. of course. This is what I wanted. Your preference may be different tho.

 

[johnny_munyak]

I haven't really thought of a vortech setup, but you have me thinking of it now!

I was originally considering a simple engine with HCI without the blower/turbo/supercharger power adders and with the intention of getting the HP in the 400-450 range at the crank....which would equate to around 350-400 Rwhp. I'm guessing my current configuration is around 275-300 Rwhp.

Perhaps I'm going overkill with a stroker windsor when a more aggressively built 302/347 could allow me to reach my goals without the other hassles of trying to get a 351 w to fit?

If a built 351/357 can get to these power levels and remain more driveable than a high strung 347, then that is definately a good thing. I dont' want to turn the car into a pure race car cause I truly enjoy driving it. With my current configuration, the fuel mileage is also very good. The car gets around 20 MPG in the city (when I'm not flogging it) and has consistantly gotten around 27 MPG on the highway cruising @ 70-75 MPH. This of course with a 5 speed and 3.55's. I was quite pleased with these numbers since I was concerned about the fuel mileage going into the toilet after the HCI swap. I don't want a garage queen.

At the same time, If I put in a 351w into the car, it has to perform cause it's no darn fun telling everyone it has a 351 installed in it and then someone with a high strung 302 or 347 hands your ass to you.

I guess you can't have your cake and eat it to, but it is sure nice to try!

Obviously there will be some machine work to get the 302 to 347 status along with different rods/pistons. The 351 could get away with a crank polish, bore honing and some new rings, or if worse came to worse, punch it out to 357 and get new slugs and rings. Have the rods checked over and the bottom end would be good to go. ...or go all out and get a 393/408 stroker kit. Am I wrong to assume that a well built 351 w would not hand a 347 its ass in a handbag? Originally, that was the goal......to build a cheap engine that could eclipse the power of a 347. Seem kind of silly to go through all the trouble of getting a 351 into the car and then having to stroke it to 393 or bigger just to beat the 347?


Now, the vortech thing is also interesting. If the same power levels could be had by rebuilding the stock shortblock with a more stout crank/rods/pistons, utilize all of my current H/C/I setup and install a vortech, what would the cost comparison be?? How streetable will it be?? My current cam and heads should do just fine with a vortech all of which should fit neatly under the factory hood. Only thing that would give it away would be the whine. ;0)

Sound kinda like fun too? What are kits worth for a 95' GT??

 

[final5-0]

I haven't really thought of a vortech setup, but you have me thinking of it now!

I was originally considering a simple engine with HCI without the blower/turbo/supercharger power adders and with the intention of getting the HP in the 400-450 range at the crank....which would equate to around 350-400 Rwhp. I'm guessing my current configuration is around 275-300 Rwhp.

450 flywheel X .85 for drive line loss is about 383 to the wheels

Can be done with a 347 without a bunch of effort
and
It would be fairly tame with a sharp tune

That level is not gonna require a bunch of stuff like forged this and
forged that

I guess you can't have your cake and eat it to, but it is sure nice to try!

Well ... what this thread is all about is seeing how close you can
come to making that happen

Now, the vortech thing is also interesting. If the same power levels could be had by rebuilding the stock shortblock with a more stout crank/rods/pistons, utilize all of my current H/C/I setup and install a vortech, what would the cost comparison be?? How streetable will it be?? My current cam and heads should do just fine with a vortech all of which should fit neatly under the factory hood. Only thing that would give it away would be the whine. ;0)

Sound kinda like fun too? What are kits worth for a 95' GT??

Again ... Your desired RWHP objective is not block splitting power

For a STREET CAR .............
Why Do You Think You Need All That Fancy Stuff

Grady

 

[johnny_munyak]

What fancy stuff I may/may not need is what I'm trying to figure out!

I would love the idea of a stroker 351w, but if the cost to build it is outrageous and complicated to install, yet by simply bolting on a supercharger for $3000 and I could have 450+ HP and leave everything else alone?

By the time I'd buy better heads, intake, cam, headers, etc, etc for the 351 to get to the same power level, I dare say it is going to cost me much more to build this engine and to get it in the car?

However, I'm not leaving much room for improvement on the stock 5.0, but perhaps I don't need anymore? A 450 HP daily driven work/street/summer car is nothing to sneeze at. A 351w will give you almost infinite possibilites and HP levels should you decide to go that route, but this is not a race car competing for points and standing and dollar bills.

If I was to put in a built 351, there would be no use penny pinching and dinking around because this would probably be the LAST engine the car would ever see while it is in my hands.....so going to a 393/408 should be the goal?

Nice thing about the supercharger idea is that should you ever decide to sell the car, removing the supercharger and putting it back to stock should be done easily yet still give you the option of selling the blower and getting majority of your money back late on should you decide to do so.

Is the stock 5.0 block capable of handling 450 -500 HP safely and reliably using a supercharger?

 

[revhead347]

450hp on a stock block isn't too outrageous, but you will have to do a few things to the engine. Probably going to need to swap out the head gaskets at least. You are going to need more than $3000 for a few other things, like a larger fuel system.

Kurt

 

[final5-0]

What fancy stuff I may/may not need is what I'm trying to figure out!

I would love the idea of a stroker 351w, but if the cost to build it is outrageous and complicated to install, yet by simply bolting on a supercharger for $3000 and I could have 450+ HP and leave everything else alone?

By the time I'd buy better heads, intake, cam, headers, etc, etc for the 351 to get to the same power level, I dare say it is going to cost me much more to build this engine and to get it in the car?

However, I'm not leaving much room for improvement on the stock 5.0, but perhaps I don't need anymore? A 450 HP daily driven work/street/summer car is nothing to sneeze at. A 351w will give you almost infinite possibilites and HP levels should you decide to go that route, but this is not a race car competing for points and standing and dollar bills.

If I was to put in a built 351, there would be no use penny pinching and dinking around because this would probably be the LAST engine the car would ever see while it is in my hands.....so going to a 393/408 should be the goal?

Nice thing about the supercharger idea is that should you ever decide to sell the car, removing the supercharger and putting it back to stock should be done easily yet still give you the option of selling the blower and getting majority of your money back late on should you decide to do so.

Is the stock 5.0 block capable of handling 450 -500 HP safely and reliably using a supercharger?

Lets be sure we are talking about RWHP here

Most say 450 RWHP is the limit for the 5.0 OEM shortblock

Having said that ...........

I've always felt it kinda silly to have a nice h/c/i combo that lays down
about 300 to 325 to the wheels and then go for a blower or turbo as
that would push it over the limit

See ... that is what is hard to dismiss about using a pa ........
You can obtain 400 rwhp give or take a few with a blower or turbo and
not need the best h/c/i and the like and still be using an OEM 5.0 sb

You just need to feed it with plenty of fuel
and
You need a tune to make it safe and driveable with the big inj's

When you cram down the mix .........
You just don't have to be as particular with combo parts
like when all you got to force the mix is what mother nature provides :Word:

All you gotta do is search with a focus on blown combos and you'll see
peeps making around 400 without the best of everything

Again ... Not trying to say a pa is the best way
but
It is a way to go beyond what a NA OEM 5.0 combo will do
yet
Still use the OEM sb if you don't wanna go beyond 450

Grady

 

[Pokageek]

Yep. It is expensive to go the 351 route though. My headers were roughly $900. For the 5.0 they can be had for $650 + shipping with the mid-pipe. If I wanted less headaches and simply 450rw - and didnt care about the low end grunt as much, I would go 347.

I SAY THIS bc to get 450 out of a 347c.i., would be like getting 517rwhp out of my 414c.i.. You are well past your 1:1 ratio. This means you will give up lots of low end as you are pushing the power band up higher and higher. Yes you can counter it with gearing but it remember, you are going to have a ROCK 'N ROLL cam at a stop light (got on my nerves) and 32V like driveability, meaning you must go higher to get the power. This is not my preference but if its yours, then go for it.

All I am saying is b4 you lay down the cash$$$$$$$$ make sure you are not just thinking like a Quarter Mile-R in terms of a TOTAL RWHP bragging number, and make sure you are gonna like its driveability!!

Oh, and BTW, there will be plenty of blown combo's that will still get up and walk you after all that. It never ends. ..you always want more. I remember after I was all excited about my big c.i. motor and then getting int0 a friends cobra. He put a pulley and exhaust chip and was putting out more rwhp than me. I wanted to puke at the time.

 

[johnny_munyak]

Precisely. A torquey car with broad power band starting lower in the range is more fun to drive and more streetable than big HP numbers at 6000 RPM. Not what I'm after.

A 351w stroker should be a torquer engine and pull well in the lower RPM range, but by the sounds of things, neither option is a cheap one. HP don't come cheap and I'm starting to see that. A vortech/ken belle setup is going to be over $3000 and then there is the fuel system that WILL need to be upgraded. Not a Huge expense, but when added to the cost of the kit, is very costly as well.

As most have said, even with all of this, there is ALWAYS someone faster......DAMN that freakin' HP bug!

 

[94GT for me]

I have been flip flopping on this as well, but I always ome back to the 351, for a few reasons.

One, and mainly, I like massive torque in these cars over high rpm HP. A stroker 302 can put out nice HP, and you can up the torque some, but bottom line is the 302 has a longer stroke then bore and was designed for more ft/lb then HP. RPM and air/fuel changes can overcome that, but it makes the engine pretty wild the higher you push it. For a street car/daily driver, wild isnt the goal IMO.

A 351 offers even more guts, and a similar amount of HP with some upgrades, but doesnt go over into that wild area. it will put down solid HP in the stock RPM range, with a significant amount of torque over a 302. This wont make it the uber fast 1/4 mile car, but if your goal, like mine is, is to make a car for cruising around, it will be a lot easier to navigate through town etc because of its mild manners. low end grunt and a reasonable cam is just easier to deal with when you are at the stop light behind the guy in his toyota.

There is one other thing-people talk about the heads and whatnot not being able to flow well enough, hood clearance etc. In one of the posts just above someone mentioned the blower option. Solid HP out of mostly stock or otherwise mediocre parts because the air is forced through. Why not do this on a 351? I might be missing something, but in the future, as we gear heads always like to dream about, instead of a 408 stroker kit, why not a turbo or blower? put the cobra upper on the 351 to keep the hood lower, and slap a turbo on it instead to gain some HP to go with the guts? A single turbo would also have the benefit of not putting significant boost on at lower rpm for that mild mannered town cruise, but would increase the power band's size, not just move it up the rpm scale.

So, why not have your cake and eat it too?

 

[302GTS]

I'd probably go 351... By the time you add a Vortech, you'll be literally sitting on the thin line of power limits for your stock shortblock. Personally, I'm going to start saving for a Dart blocked 351 in the future, mild h/c/i, and a turbo, with full interior (street car! ).

That low end torque is what makes the car fun to drive with a 351, too! I've driven low torque/high HP cars before, and it just doesn't do it for me. There's something about laying the throttle down and being pushed back into the seat that's really addicting, and I wouldn't want anything else!

 

[revhead347]

One, and mainly, I like massive torque in these cars over high rpm HP. A stroker 302 can put out nice HP, and you can up the torque some, but bottom line is the 302 has a longer stroke then bore and was designed for more ft/lb then HP. RPM and air/fuel changes can overcome that, but it makes the engine pretty wild the higher you push it. For a street car/daily driver, wild isnt the goal IMO.

Stock stroke on a 302 is 3.0" with a 4.0" bore, so the bore is longer than the stroke. Both a 302 and a 351 have essentially the same bore (Ford advertises the 302 with a .0006" bigger stroke than the 351, but I dont' know how accurate that is). Longer stroke generally gives you more low end torque.

Kurt

 

[nmcgrawj]

Accufab has headers for a 351 that are custom and fit really well. $500. Simple H pipe...less than 200. Always remember there is more than 1 way to skin a cat......


Also i'd like to note if you do put together a "basic" 351....with a factory rotating assembly....im gonna bet that if someone in a similar car, with a 347 and the same h/c/i/tune races you, you will lose. The rotating assembly in the 351 is heavy. Ofcourse, Once you go aftermarket this margin shrinks....and is obviously negligible when you get way up in the cubes comparing a 400+ cube motor to a 347.


And really, how much torque down low is simply too much? If its going to be a street car....its not gonna be fun being on ice skates through 1st and 2nd gear and probably 3rd. If you can actually use the torque, then great. But if it just breaks lose....you arent using it and at that point you can only brag about it. I think if you go into a project with a 302, 331, 347, or a 408 and you want a street car with a strong idle-6,000 window, all of them can do it. Traction in the 302 will probably be relatively easy....and the 408 relatively impossible. LOL

 

[Pokageek]

Go 347.

 

[nmcgrawj]

Go 347.

u ever make any progress on your tune?

 

[BlackVert]

if i had a running 351 ... and a garage and time ... and i knew what i know now, i would have done mine very differently if i were doing it again

i would have still gone 351, but my plan and process would have been completely different

i would first do the BARE MINIMUM to get the 351 in the car and running. that would mean mainly headers and intake. but i would leave AS MUCH AS POSSIBLE as it is. again, the absolute bare minimum to get it in the car and running. the one thing i would not skimp on is the intake ... i would get an intake i could use with my final combo

then i could (and would!) drive it like that while i was planning (and saving) for the final version the motor would take ...

the real benefit for me with this approach is that the car would be on the road alot more (really important to me) and i would still have the benefit of the better torque in the every day rpm range.

if i decided to stay 351 and not stroke it, then it's just a heads/cam upgrade.

if i decided to stroke it, then it's just like any other stroker rebuild