351w or 347 stroker? which is better?
 

Given the choice, which combo would be better for street,strip use, a stock 351w or a 347 stroker? I have both a 351w complete motor and a 302 complete motor that would need a stroker kit. They are both non-roller blocks. Would there be any benefit to doing a stroker 302 when i have a 351w. (I would need all the conversion items for the 351 to fox body). What do you all think? Decisions, decisions...

no substitute for cubic inches..

351w would be much cheaper.

Why not just stroke the 351w to a 408? The money you would spend stroking the 302 could be used to stroke the 351.
It all comes back to how much $$$ you have to spend.

302-351w
 

I've thrown that one around myself. If You stroke the 302, you loose engine life. If you don't stroke the 351w, it lasts longer.
For me the 351W for street use is my choice. For the strip, a stroked 351w would be turning faster ET's for a few bucks more...concidering it all costs alot $$$$ in any case.

If you want the motor to last more than 50K miles use the 351W

Dollar wise I'd go with a 392ci stroker. If I remember right a 392 is a 3.85" storke crank, 351w rods and 302 pistons. FRPP sells the crank (I think it's like $500?) and if you can't or don't want to use the 302 pistons you have, stock type pistons should be cheaper than the stroker ones.

IMHO
Brian

Where is Clawson,MI

i have a 347, and to tell you the truth i could have built a 351 for the same exact price. (a stroker) check out ebay, there are companys on there with ebay "stores" and they have everything for a stroker, (i would piece one together) forged 347-408 cranks for 300.00 brand new. you will save probably 200.00 on each thing you buy if you go through ebay. i would only buy from the stores though and from people.

A 347 will make more power then a 351 in the SAME conditions.

I would go with the 351 just for longevity. I'm sure the horsepower numbers are close to being the same and the 351 is almost garenteed to last longer.

I would go with the 351 just for longevity. I'm sure the horsepower numbers are close to being the same and the 351 is almost garenteed to last longer.

You should probably explain that.

I think what WADS56 was trying to say is that if both engines had same compression,heads,intake,cam,induction and exhaust etc. that the 347 would still make more power than the 351.
Actually, a 347 really has 350 cubic inches of displacement but they didn't want to advertise it as a "350"

I am not trying to argue at all. I'm just curious cause I don't understand why one would make more power than the there. Even being a 350 as you say I still don't understand. If every part of the setup thats affects flow or power production on both motors (compression, heads, cam, ...etc), why will one make more power than the other.

I was waiting for someone to call me out on that:p A 347 which uses a smaller crank journal than a 351 will free up a few ponies right there. Also, the .030 over bore on the 347 will hep the intake flow beter then the 351 with the standerd bore. This will not make huge power gains over the 351, but it will make more:D And as far as the 351 lasting longer....? I don't agree with that either. If it was a 600hp motor then yes, a 351 is a much stronger block. But if this was a 350-400hp motor, they will last the same.

Wade

Thanks. I had a feeling it was something like that. Can someone tell me which is better for longevity smaller or larger crank journals. I would guess smaller.

It might make a little more HP but will it make more torque?
Torque is what give you the low E.T and HP give you the MPH at the traps.
Does the 347 have a longer stroke than the 351w?
With all things being equal, then I would say the engine with the longer stroke would give you a slightly better E.T.

A 347's stroke is 3.400 and a 351 is 3.500. That is very little and I'm not sure if that will even make a difference. Were talking about 4 little cubes here which is nothing. Look at it this way the .030 overbore makes up for the 4 cubes, and the smaller journals the 347 has put it over the top. Now if you stroke the 351 that would change it all

I dissagree. The rod/stroke ratio on a 347 far worse than the 351W. The 347 will be using oil WAY before the 351W. Which is why I say.....If you want the motor you last more that 50K miles, go with the 351W.

I'm not an expert by any means - but I've heard a punched out 302 to 347 is a good powerplant but it's not reliable over the long-term.

my 2cents - all these posts pretty much say the 347 and 351 are pretty close. if you've got both blocks I would suggest going with the 351 as it can always be stroked to 392 or 408 I believe.

That is not true. This is a MYTH that just won't die. Machine work will make or brake any engines life. All this "rod to stroke ratio, and oil ring thing" was a false statement so people would buy the 331 strokers from the selected few that offered them when the first came out. They made a killing off this, and now the myth has been spread all over the internet and people buying in to it.

WADS56 - I see from your sig you've got a 347, how many miles on it? Are you saying the 347 is realiable and won't use oil with miles on the block?

All these posts are good info for my son and I as long-term we've got plans for a new motor in our stang. We've looking at everything from a 306 up to a punched out 351.

I am saying that a motor is only as good as the parts and the machine work that go's in to it. I myself don't know how many miles are on it because I don't have a odomoter. I can tell you that i have beat the crap out of it for two seasons now and it has no oil issues or anything. In fact it is tore down now and you can still see all the honeing in the cylinders. If 347's have a bad rod ratio I would see ware in the cylinders by now from the piston side loading on the wall. A good rule of thumb is... If it is a oil burner from break in it will be a oil burner all its life.

Have to agree with WADS56. I keep hearing this "oh, I heard this about the 347"...that it burns oil, and has a "bad rod ratio". Same rod ratio as a chevy 350, and they built millions of those. I have yet to have anyone give me first hand knowledge of these "bad" 347's". Coast and FPS now have pistons with the pins removed from the ring land area. So far I am happy with my 347, 98 % drag race application, but no probems yet and great power.

Ron

I had no oil probs with my 347 when it was running...Just tore it down to upgrade some parts(heads, intake, cam..etc) and having a hard time getting things back to normal...

"The primary reason for longevity issues was the oil ring in the wrist pin area. That problem has been addressed by several manufacturers. But, they still push the rings too close to the wrist pin, and have a rod/stroke ratio a little on the nasty side from my understanding The extra cubes you get going to a 347 from a 331 are minor, and not worth the possible reprocussions in my opinion"

RON1: The reason a 350 chevy has no problems with the same rod ratio is beacuse of the taller deck height.

Personally, if i was to stroke a 302 the max I would go is a 331. Been than again i am running a 306 and run circles around most 347's. I have seen a 306 make well over 600 n/a rwhp and have seen 306's into the 8 sec range. They say there is no replacement for displacement .........N2O......the displacement replacement....

just my 2cents

331's have the oil ring in the ristpin area as well. And yes the rings are a little tighter on the 347 but that is not a issue. The only advantage that a 331 has over the 347 is in a power adder app. There is some more meat on top of the piston on a 331 to handle the abuse a little better.

And yes nitrous is a replacement, but i can put nitrous on my lawnmower.

sure, but you don't know how to tune it. :)

so your saying that i might have a little problem with a 300hp fogger kit, w/347 5.4 rod 8.5:1 combo?? i have the pms and it should be tuned perfect, do you think ill have a piston problem.

btw:i have je/srp 8.5:1 pistons

Are you using the turbo, or nitrous? 8:5 is a very low compression ratio for a nitrous motor it is perfect for that turbo though. Anyways... if you are spraying a 300 shot on your 347 with the stock block your pistons should be fine untill they get blown through the oil pan:eek:

yeah i found another turbo to get but i dont think i can afford it until next year so i figured just spray it 300 until i can afford the turbo. you guys think it'll run pretty good with 8.5:1 w/300 shot? or do you have something else that i can do in the meantime.

any suggestions??????????

hopefully the crank/block will hold up with my abuse:D

it would run better with more compression. If your motor can handle it...sure go for it.

i have a main support, eagle forged crank(4340), eagle h beam rods(4340) and je/srp 8.5:1 pistons(forged) with that low of compression do you think it would be able to hold up with a 300shot.

with it being perfectly tuned with race gas???

just need some opinions thanks

stroker life
 

Don't you loose engine life , because of a shorter piston skirt with a stroker in the 302>347? My understanding was a 302 stroker piston had less of a skirt.




Oh.. Clawson Michigan is just north of DEtroit...

I gotta back my buddy Wade here...
I can honestly tell you for a fact I have seen Wade beating the crap out of his 347. This guy leaves the line like a raging Pitbull on Steroids. I've seen him break everything from axles to crossmembers. And he knows his poo. I am a firm believer that if a 347 can hold up to the kind of abuse this guy dishes out you have absolutely nothing to worry about. Just look at his parts list, copy the build, and find a good engine builder. It'll last forever on the street ;)

Another issue I haven't seen anyone bring up (or I missed it) is the fact that the 351W block weighs something like 50lbs heavier than a 5.0 block (correct me if I'm wrong please). I'm not up on how much horsepower 50lbs of weight added to your car is comparable to, but you get the idea.

Thanks for the kind words <(insert embarassed face here). Also, thanks for reminding me about all the money I spent on replacing broken parts:( I was trying to forget about that:)


Good advice though. "Find a good engine builder and it will last a long time"

i mean w/ 300shot, im sure it'll last a long time n/a but i dont think thats going to be enough for me. what do you think the longevity of a 347 w/300 hp fogger kit would be?

5.3 rods
 

if there is concern about the "so called" oil ring problems just get the 347 kit with the 5.315 rods and that will alleviate that problem.

I haven't followed the entire post... what block are you using?

A stock block will not reliably hold a 300shot... I had just over 60 passes with a 200shot on a stock block 306 combo before the block split. A B50 block w/ a girdle would maybe do a better job, but still is pushing the limits, and wouldn't last a long, happy life.

The ONLY way you're going to put 300hp of nitrous to a 400hp+ n/a 347 is to go with an R-block or Dart block.

And, yes, I also agree with Wade and 2Fast that the 347 is a more desireable combo over the 351... all things being equal, of course. Now if you stroke the 351 it's a whole new ballgame. ;)

ok hopefully i dont grenade the darn thing, it will mostly be just for street racing. so it shouldnt see more than 20 passes this year, at the end of the year im going to buy a dart block, and hopefully then it will take whatever i throw at it.

Every 100lb you take off is worth about a tenth in the 1/4 mile.
So you are talking only about about a .05 difference in E.T

How many 1/4 mi. races will you do on the street? lol ;) ...it all adds up, pretty quick! :D

Have you considered going with a smaller nitrous kit, maybe a single nozzle before the throttle body via NX, or even one of their new EFI plates that sandwich between the upper and lower intakes? ...the 300hp fogger setup would be a bit much, IMO. :)

-Ryan

could i spray 250 through a single fogger nozzle (wet kit) also how would that work do i just put a t before my fuel rails (i have an aeromotive setup) and run a gas line straight to the selenoid? i dont see how the nozzle would see enough fuel pressure to evenly distribute the nitrous and gas. the plate's for the efi systems are rediculously priced ($500+) so i dont want to do that, (i havent seen one for the victor efi intake yet). if i could run 250 through a single fogger nozzle i will do that.

the reason i want to spray so much is because i only have 8.5:1 compression, cause as soon as i can afford a precision ball bearing t76 turbo, im going to pick one of those up.

I sprayed 200hp through a single nozzle before the t.b. on my old combo this year, and the kit (NX EFI Race 20113) is adjustable in 100-150-200-250hp increments.

Also, NX makes a plate for the Victor 5.0 intake, as I will be stepping up to one in the future. ;) I'm going to start with the kit I already have once I get the new motor together, and add the plate later to make a two stage system.

As for fuel supply, I went off one side of the Paxton universal EFI regulator right to the solenoid. I run a line from the pump to a -8 NOS Y-fitting with two -8's to the rails. From the rails, two more -8 lines to another NOS Y-fitting, into one -8 line that goes to one side of the regulator, so I had the other side blocked off until the nitrous system was hooked up.

I picked this up on one of the other sites...maybe even here...

Originally posted by George Klass, CHP
"This rod/stroke ratio stuff is really not that big a deal for high end street racer type engines. How many of you older guys remember the old Ford 292 inch Y-Block engine? Generally considered a piece of crap; not much performance and not a very long lasting beast, either. Rod/stroke ratio? 1.91:1. Here are a few engines with their rod/stroke ratios: 454 Chevy - 1.53:1, 455 Pontiac - 1.58:1, 428 Ford Cobra Jet - 1.63:1, Ford SB 331 Stroker - 1.60:1, Ford SB 347 Stroker - 1.58:1, etc. The most important rod/stroke ratio to be concerned with for most street/strip racers is 8:1. Eight rods to one crank. As far as displacement is concerned, here is something to contemplate. NHRA penalizes displacement in all Comp Eliminator classes (weight to cubic inches). Now, why do you think that is? If bigger inch engines didn't have more HP potential, somebody needs to tell NHRA. There is nothing wrong with a 331 OR a 347. Take your pick. But don't get stuck with all this "theory" (side loads, rod/stroke, rod angles, etc.)"


(Quote)
Originally posted by George Klass
What follows is not an opinion, however. A CHP 347 Street Fighter will last as long or longer than a 331 or a 302. This is because of the exclusive oil control feature (discussed elsewhere on this board). Does anyone really think that a 260 or 289 will last longer than a 302?

(Quote)
Originally posted by George Klass
I have read all of the interesting and logical (and not so logical) reasons for choosing a 331 over a 347, and everyone of those reasons could apply to choosing a 289 over a 302. Which would you choose?

Just FYI

Ron

Thanks Ron, I had read that awhile back on Hardcore50.com ;)

The reason I remember where I read that info is because those two sentences stuck with me, as I nearly fell out of my chair after reading that, lol, thinking to myself "Oh, so very true!" :D

just curious what selenoids they were, or equal to (nos) cheater, pro shot????also what jet sizes did you use, to get 100-200-250

I have noticed that you keep coming back to your compression ratio. As long as you use the right fuels it should never be a concern. I run 12.4 C/R so far only a 150 horse shot, but everything is geared to run 250 HP (If it will hook). As long as I have the right fuel, VP C16 in this case, I have no worries. C/R should not be calculated into the size of the shot. I would look at the cam...wider LSA, and a a bit more duration on the exhaust.

Ron

Unless you use an NX shark nozzle, the jetting would be different with a brand X nozzle... I have my jets out in the garage, and can post the jetting for each shot in the AM if you like.

As for solenoids... NX uses large solenoids in their kits. Go to www.nitrousexpress.com and have a look around to get an idea what I'm talking about.

If you are going to run NOS solenoids and nozzle, you'd be best off to get jetting specs from NOS. I wouldn't recommend using the jetting specs for an NX system, or any other brand system for that matter, as all manufacturers do not use identical jetting patterns for their hp ratings with various kits. I noticed that when I installed a NitrousWorks EFI t.b. plate on a buddy's '93 Cobra a few months ago. ;)