347 vs 393... Pros and Cons

oxemoron

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Jul 12, 2003
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Hey could you guys please explain the advantages each engine has, and is it possible for me to create a daily driver 347 from a factory block? Also would it be a large price difference because of it being a bigger engine and requiring many swap parts? I'm just looking to keep things simple and not get myself into a project thats over my head.
 
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First Question: How big is your budget? I think the best thing about owning a Mustang is all of the options available

Next: Do you have a 351 block to make the 392/408 stroker out of? There used to be a sticky with the 351 swap information in it. You would need new motor mounts, lower intake, headers and a few other things... Too bad that stickey disappeared.

The stock block can be clearanced for a 347. You'll need to add larger heads, better intake (replacing the stock parts) and pay for all of the new stroker parts. The limiting factor in the stock block will be around 400 - 425 RWHP to avoid splitting the block.

Don't forget that you will need to update your fuel pump, probably the brakes and your drive train if you want to see the most out of the combo.

Now, can it be done as a daily driver? Of course as long as you don't go too crazy with the cam selection and cluch choice. You should be prefectly fine driving that car around everyday.
 
393 will make more power and will be more expensive.

A good built 347 can put down 400/400 @ the RW NA on pump gas. A stock 302 roller block is good to 500rwhp if u want to throw boost on it.

A good built 393 can put down 475/475 @ RW NA on pump gas.

I would do a 347. Scat 4340 forged profiled crank, Scat 4340 forged H-beam rods, SRP 10:1 flat top pistons, balanced to 28oz, AFR 205 heads or TFS TW 205's from Summit, Comp Cam XE282HR, port matched Victor or TFS-R intake, 30lbers.

Almost all these parts can be bought from adperformance.com. OR u can have a crate motor built from CHP, panhandleperformance.com or the above addy.
 
304billet said:
393 will make more power and will be more expensive.

A good built 347 can put down 400/400 @ the RW NA on pump gas. A stock 302 roller block is good to 500rwhp if u want to throw boost on it.

A good built 393 can put down 475/475 @ RW NA on pump gas.

I would do a 347. Scat 4340 forged profiled crank, Scat 4340 forged H-beam rods, SRP 10:1 flat top pistons, balanced to 28oz, AFR 205 heads or TFS TW 205's from Summit, Comp Cam XE282HR, port matched Victor or TFS-R intake, 30lbers.

Almost all these parts can be bought from adperformance.com. OR u can have a crate motor built from CHP, panhandleperformance.com or the above addy.


Why would you put a forged crank in a stock 302 block?


I think it also depends. If you are starting from scratch...then u will need to buy a lot of the "swap" parts for the new motor anyway. Motor mounts are not a must. If u need them...you need them. If u dont...well then u dont. A 351 doesnt require different mounts.

Some guys have a hood already...so thats one less thing for a 351w based motor. Unless u figure out how to drop the 351, you will need a taller hood.


Search around. There was a thread here along with a thread on the corral. Like i said, if u already bought a lot of 302 stuff, then stay there or you could sell it like i did and go 351. If from scratch, it would bea lot closer in price but the 351 will still be more to do. But, it has its benefits to go along with the bigger price tag.
 
nmcgrawj said:
Why would you put a forged crank in a stock 302 block?


I think it also depends. If you are starting from scratch...then u will need to buy a lot of the "swap" parts for the new motor anyway. Motor mounts are not a must. If u need them...you need them. If u dont...well then u dont. A 351 doesnt require different mounts.

Some guys have a hood already...so thats one less thing for a 351w based motor. Unless u figure out how to drop the 351, you will need a taller hood.


Search around. There was a thread here along with a thread on the corral. Like i said, if u already bought a lot of 302 stuff, then stay there or you could sell it like i did and go 351. If from scratch, it would bea lot closer in price but the 351 will still be more to do. But, it has its benefits to go along with the bigger price tag.
i was thinking the same thing....the block is going to break before you can even begin to touch the cranks potential
 
Well as far as my budget goes, i dont necessarilly have one i just want to try to keep it fairly low. I plan on making this a project... I wasn't going to buy all the parts at once, i was going to do it in steps so i dont leave myself broke. My goal is 450RWHP with no power adders. I'm just having trouble deciding between a 302 stroker or 351 stroker. Which setup would cost the least and achieve the 450RWHP goal? Also would a stock low mileage 351 short block be capable of that with bolt ons, if not would changing the pistons and rods help?
 
The 351W stroker will add cubes, but will also add weight. It will most likley cost a lot more. You could easily spend twice as much on a 302W stroker than a 351W and also make twice as much power. It's all in the build. The 351W stroker will not make more power if it can't breath better. When building a powerhouse, the shortblock is just the foundation. You can build a bigger house on the larger foundation, but it will cost more.

I'm doing a 347, now that I have dug this deep, I kind of wish I did a 408-418-427+ because I have swapped so much anyways. Probally a SBC would have been even better, cost a lot less, but this would just lead to the questions of a bigblock. Guys are running 10's in the 1/4 with pump gas streetable 347's. It's all in the build. Contact Rick 91GT he'll set you straight.
 
Find a good 351W block,get your self a 418 stroker kit with a cast crank,I-beams,and some decent pistons.

Have it about 11:1 compression and put decent 205cc heads on like the AFR 205's,205 TFS TW,or lightly worked Victor Jr.s.

Cam should be a custom,other wise a TFS stage 3.

If its carbed,Victor Jr intake port matched to heads with a 850.

If EFI,TFS R intake with 36-42lbs injectors.

And the same parts on a 351 would make over 450hp,just you will need a little more rpm.
 
oxemoron said:
Well as far as my budget goes, i dont necessarilly have one i just want to try to keep it fairly low. I plan on making this a project... I wasn't going to buy all the parts at once, i was going to do it in steps so i dont leave myself broke. My goal is 450RWHP with no power adders. I'm just having trouble deciding between a 302 stroker or 351 stroker. Which setup would cost the least and achieve the 450RWHP goal? Also would a stock low mileage 351 short block be capable of that with bolt ons, if not would changing the pistons and rods help?


Just my opinion, but i would not build a 450rwhp motor in a stock 302 block. Some have held...others havent. I wouldnt spend all that cash on a 302 stock block and be walking on thin ice. If it breaks, i, like yourself it seems, wont have money to go back and do it all over.

If you want 450rwhp, thats a nice number but you will have to pay to play. Short of going with a dart block, the 351 will be your "cheapest" and SAFEST route. You can go cheap but if it breaks, what does it matter?

Oh yea, i havent researched them, but you might want to look into mexican 302 blocks or the sportsman. I dont know the differences and whats needed and not needed compared to a 351, but its another option.

Like i said, i wouldnt push 450rwhp through a stock 302 block. Definately think twice about that.
 
Aliate X said:
460 big block would make 450rwhp with stock ported heads.

You dont need or want the big block for only 450hp.

All iron 460 vs. alum headed 351W probably close to 200lbs.

But your right,it would be cheaper and in a straight line be faster (cause of the massive torque).
 
Aliate X said:
460 big block would make 450rwhp with stock ported heads.

I know 460's can make great power, but how easy is the swap? I have seen a couple of guys who have done it in fox's and sn95s. You would still rebuild the motor correct? So the machining costs are the same. Im not sure of the details but thats an interesting option.

And i thought the days were over of "a chevy being cheaper to build" ?
 
Note I said used parts,new stuff is about the same now,its just cause of the volume of used Chevy parts.

Check out www.racingjunk.com and you'll see what I mean.

I dont know about the LS1,I guess you could just consider it a GM motor because they use its basic desing in almost everything now.
 
v

nmcgrawj said:
I know 460's can make great power, but how easy is the swap? I have seen a couple of guys who have done it in fox's and sn95s. You would still rebuild the motor correct? So the machining costs are the same. Im not sure of the details but thats an interesting option.

And i thought the days were over of "a chevy being cheaper to build" ?

HEY GUYS, the network 54 429/460 forum has moved to www.460ford.com , check it out.

Theres a few guys who have done the 460 swap into 94-95 mustangs on the 429/460 board. Its pretty straightforward and easy as swapping it into a fox almost. I'd say biggest bang for the buck for straightline performance, a 460+ is the way to go. Im very very very happy i did the 466 instead of a 347, that torque is just crazy. Mine is a kinda crazy setup for a weekender, but it drives great and i have power until 6500 rpms. Nexttime mine is out of the car, it'll be a 521, thats only a .030 overbore and a 4.3 stroke and the great thing is the factory blocks can handle ~800 rwhp no problem. I spent ~ $6100 on my built only because i went crazy with parts from summit, but theres PLENTY of performance parts out there for 460s, dont let anyone tell you their isn't, if they do, they dont know ****.
 
bluevenom867 said:
You dont need or want the big block for only 450hp.

All iron 460 vs. alum headed 351W probably close to 200lbs.

But your right,it would be cheaper and in a straight line be faster (cause of the massive torque).
i believe it is actually closer to 270 lbs difference. so the 460 better make at least 50 or close to extra hp to just compensate for the weight.
 
I have to agree, a big block is definatly a way to go. Maby in the future I'll do something like that. That is a lot of weight over the nose of the car, it's going to take some serious traction to get it moving. It seems though that small blocks are more common in the faster cars.
 
everybody thinks its like a huge amount of weight on the front end, on my car, seriously, it feels like having a fat kid on your hood, stopping isn't that much different and im running stock 5.0 suspension and steering. It still can go around corners pretty good, traction is however an issue with any big block in a light car.

I do miss the 302's gas mileage, but i'll gladly trade that for the torque of this monster. I was gonna do a superchraged small block combo, but i had a DD and i didn't want to be like evryone else, so i built a 460. I never regret it.

If anyone wants to come to ohio this spring i'll gladly take you for a ride in my car :) you just have to spring for gas lol.