Vintage Mustang Forums banner

1 - 17 of 17 Posts

·
Registered
Joined
·
341 Posts
Discussion Starter #1
One thing about my project being another 1 away is that I have time to think and over think my motor choice. I have this reminder that there are no subs for cubs. I've been kinda dead-set on a 5.0L/5 speed out of late 80's to early 90's Fox body.

A couple of days ago I got a great deal on a 65 Mustang T-10 for $100 and it's in great shape. I know all about the T-10 and it's strength rating so this is not what this is about. What I'm wondering is the fitment differences between a 302 and a 351. I know with some of the great big motors you can't even get at the spark plugs. I'm just wondering how tight a 351 is over a 302. I don't want to have major clearance issues with headers and not being able to read spark plugs. So how does the 351 fit in there? Trying to figure out why spend the money on a 347 stoker kit + machining when I can just buy a 351? Any thoughts??? Thanks!

P.S. I will absolutely be dropping the $$$ for aluminum heads. Leaning toward AFR Outlaws but will concider Twisted....GT40.....etc.....So factor in really good, late technology heads with your advise. Thanks!!!
 

·
Registered
Joined
·
764 Posts
Something to keep in mind...I have asked the question of which engine will make more power before and I always hear the 347 stroker will outrun a 351w. That being said a 351w stroked to a 393/408 etc...will outrun both.

I would say build the 347 and you will know for a fact that it will fit perfect and make all kinds of power (400-500hp depending on combo)

Ok now time for someone who has a 351w based block in a 67/68 to chime in...
 

·
Registered
Joined
·
341 Posts
Discussion Starter #3
Well.......I think I need to jump in and restate that this is largely a fitment issue. I realize that you can get a V-6 to produce unreal power if your pockets are deep enough.

Actually....I realize now that I did dip into power and performace because I threw out the aluminum heads. I know that doesn't affect fitment so I already own you an apology! lol

I also want a roller cam. I understand that those 5.0's will be at least roller cam ready in the right years. What about a 351? I know with chevy, the retro fit lifters are speeeeeendy. Is this the same with a 351 or did they build those with factory roller cams? Thanks!
 

·
I won a special award
Joined
·
7,409 Posts
You'll have plenty of room. Here's a picture of my 351w (it's been stroked to 393) in my 70. 67-70 Mustangs are the same under the hood. 351w motors came in 69-70 Mustangs from the factory.

http://i187.photobucket.com/albums/x253/maxum96/mustang/enginebay2.jpg
 

·
Registered
Joined
·
341 Posts
Discussion Starter #5
You are a show-off Mr.! lol

Looks great. What heads ya running? (nevermind...I just saw your sig. Them's sweeeeet).

Is it the FE's that start getting tight? Or motors that start with a "4" (cj scj)??

I know they regularly put in 390's. Are they bigger than the 351 width wise? Thanks!
 

·
Registered
Joined
·
2,809 Posts
As stated above - the 351 will fit just fine and you'll have plenty of room for maintenance items. Take a look at the Engine Bay Pics link in my sig and you'll see how a 351W fits just fine into a 67 engine bay.
 

·
Registered
Joined
·
341 Posts
Discussion Starter #8
Ryan,
Just wondering if that turd scoots? Looks like iron heads.

I remember seeing pics of this a while back. Just a gorgeous car. I simply can't get over how side scoops and a spoiler decklid with extensions can make these cars look soooooooo tough!!

Thanks and great looking engine bay!
 

·
Registered
Joined
·
230 Posts
I'm going to swing a little different direction (with my recommendation) from the majority of the guys here, even though they are all in fact correct. A 351 WILL fit, somewhat tightly...but it fits.

Here's the thing. You'll need large tube swap headers for the 351 and the heads you're looking at. That, cost wise...is a wash with the 347 (you'll need the same size headers with either motor), but fitment becomes MUCH more an issue. Take a look at these pictures:


Here's a 302, with standard height exhaust port heads, and small tubes.


Here's a 347, with .75" raised ehxuast ports, and big tube headers.

If you'd like an entertaining read...click on the 'My Mustang' link below, go to the mock up page, and see just how much fun it wasn't getting that motor to fit with those headers lol. In many places, there's 1/8" of clearance. Without the solid mounts I'm using, it would never fit. Even with 1 3/4" headers (the minimum I'd use with a 347), it would be far too tight for standard motor mounts, and that's without the additional half inch of deck height a 351 has on my high port 347.

Something for you to very much take into consideration.

Now, as for lifters, there are roller 351 blocks, but locally I've found them difficult to get ahold of. That's not to say that's the case everywhere. Also...the retrofit lifters (link bars) are quite spendy. We sell the Comp Cams version for less than most companies, and they're still pricey. Summit carries them for $530.

And finally, you have weight to take into consideration. A 351 is substantially heavier on the nose than a 347, dressed identically. I've heard some say it's 'only 50lbs or so'...but 50lbs on the nose of a car is right where you don't want it to be, and right where it will have the most impact on handling and performance. Our cars are nose heavy as it is!!

Anyway, I've tried to avoid the performance benefits of a 347, as you said it's not as much an issue as fitment...but it's difficult as that's one of the largest selling points =D. When utilizing the same cylinder head, a 347 WILL in fact outrun even most stroker Windsors (sorry Hotrodder68!), if properly designed and assembled. I know this, because I've done it before, and fully intend to do it with this car I'm running now. The smaller motors are lighter, fit better, don't require goofy swap parts (although it's easier to find a front sump 351 pan than a rear sump!), and spin up SO much faster. When comparing strokers...the lesser torque output (and similar horsepower, with faster acceleration) of the smaller motors is a blessing. I don't know about you...but easing into the throttle in a straight line and going to immediate wheel spin doesn't make for a really fun ride in my book. Nor is being scared to death of puddles or gravelly asphalt lol! I have a friend who recently put his 393 stroker powered Mustang into a wall on a freeway onramp. Irrigation had leaked partially onto the access, and he was accelerating at the edge of traction (part throttle) as it was. The car did a 3/4 spin and by the time he let out he'd slid into the retaining wall.

No fun.

Anyhow, hope this helps a little...and I fully understand only portions of it are pertinent to your question, but all of it pertains to the swap consideration...and all are things that maybe others reading (that might have different needs than you do) should think about as well =D.

Cris
 

·
Registered
Joined
·
230 Posts
Dubs67fastback said:
Ryan,
Just wondering if that turd scoots? Looks like iron heads.

I remember seeing pics of this a while back. Just a gorgeous car. I simply can't get over how side scoops and a spoiler decklid with extensions can make these cars look soooooooo tough!!

Thanks and great looking engine bay!
And for the record...I agree 150% with this. That is one ABSOLUTELY beautiful fastback =D.

Cris
 

·
I won a special award
Joined
·
7,409 Posts
Dubs67fastback said:
You are a show-off Mr.! lol

Looks great. What heads ya running? (nevermind...I just saw your sig. Them's sweeeeet).

Is it the FE's that start getting tight? Or motors that start with a "4" (cj scj)??

I know they regularly put in 390's. Are they bigger than the 351 width wise? Thanks!

Thanks for the compliment. Things get a little bit tighter when you put a 351 Cleveland in. But not a whole lot. Once you shoehorn a FE (390,428,427), then it gets tighter. And things get really interesting when you squeeze a 429/460 in a 67-70 Mustang. They will fit and there are kits to do it. I almost dropped a 429 in the car that's in my avatar picture. But ended up putting a 351C in.
 

·
Registered
Joined
·
341 Posts
Discussion Starter #12
Actually....you have given me info that I didn't ask for because I didn't think to ask for. I wasn't sure if there was a weight diff with the 302 vs 351. Pete said that they are both small blocks. I'm a chebby guy. When you say small blocks, they are all the same but I'm gathering that a 302 SBF and a 351 SBF are different?? I also didn't think that my head choice, dictating a better header, might cause me to have clearance issues. I was always guessing that the headers would be 90% of the problem. In my opinion, these cars have #2 pencils for front suspension. I'm sure added weight doesn't help although I think I'll have to do "some" upgrades to get it to handle a little better. This is all very good information.

Hey Ryan....did I tell you already your car looks super tough? lol
 

·
Registered
Joined
·
341 Posts
Discussion Starter #13
Sure don't need anything that big. The 460 chevy that's in my 68 prostreeter (in my signature) is my "wake the neighbors and set off car alarms." I just want it to scoot and go sideways. at 2,900 lbs and a posi, I don't think the sideways part will be too hard regardless of the motor.
 

·
I won a special award
Joined
·
7,409 Posts
Cris Anderson said:
a 347 WILL in fact outrun even most stroker Windsors (sorry Hotrodder68!), if properly designed and assembled.


How can that be? The difference in the weight of the internals is extremely minimal. So you're saying that if you built a 347 (302 stroker) and a 393 (351 Windsor stroker) using the same identical parts with the exception of rods and cranks, that the 347 is gonna leave the 393 in the dust? Dunno about that. You have 2 engines of virtually identical design using the same parts and the one with 50 extra cubes is gonna makes less power and torque? Sorry I don't buy that. If that were the case, engine builders would be charging more for 347's than the 393/408's.
 

·
Registered
Joined
·
2,809 Posts
Thanks for the compliments guys - very much appreciated. :thumbsup:

And heck yeah this scoot scoots - even with worked iron heads! If I can get the darn hydraulic clutch fixed this week (see thread in Mod & Custom Forum), then I'll be taking the beast to the 1/4 mile for the first time to check out its numbers. Wish me luck! :)

And best of luck over the 302/351 decision! :pirate:
 

·
Registered
Joined
·
230 Posts
Dubs67fastback said:
Actually....you have given me info that I didn't ask for because I didn't think to ask for. I wasn't sure if there was a weight diff with the 302 vs 351. Pete said that they are both small blocks. I'm a chebby guy. When you say small blocks, they are all the same but I'm gathering that a 302 SBF and a 351 SBF are different??
No problem...I'm glad to help! A 302 is different from a 351, in that the deck height is 8.2" instead of the 9.5" for the 351W. Additionally, the 302 has 2.25" mains, and 2.123" rods. A 351W has 3" mains, and 2.311" rod journals. The difference in weight of the rotating assembly is substantial, with a typical cast 347 crank weighing in around 42lbs, and a standard stroke 351 crank weighing at minimum 50lbs PLUS. 8lbs in rotating mass, just in the crank, is huge. Now add longer rods, and heavier pistons...and the difference is even larger. Now add the additional 40-50lbs for the block, and you can see the benefits.


Dubs67fastback said:
I also didn't think that my head choice, dictating a better header, might cause me to have clearance issues. I was always guessing that the headers would be 90% of the problem. In my opinion, these cars have #2 pencils for front suspension. I'm sure added weight doesn't help although I think I'll have to do "some" upgrades to get it to handle a little better. This is all very good information.
Your cylinder head choice in itself will not cause a fitment issue (unless you go with a high port like I did). However, a 351/347 with good cylinder heads NEEDS a 1 3/4" minimum header. That's where the fitment issues come in. My heads on my 347 flow 340ish intake, 250ish exhaust. I'm using a 2" primary header with 3.5" collectors...although I do admit that's also in preparation for the later 396ci 302 stroker that will be going in it =D.



Maxum96 said:
Cris Anderson said:
a 347 WILL in fact outrun even most stroker Windsors (sorry Hotrodder68!), if properly designed and assembled.
How can that be? The difference in the weight of the internals is extremely minimal. So you're saying that if you built a 347 (302 stroker) and a 393 (351 Windsor stroker) using the same identical parts with the exception of rods and cranks, that the 347 is gonna leave the 393 in the dust? Dunno about that. You have 2 engines of virtually identical design using the same parts and the one with 50 extra cubes is gonna makes less power and torque? Sorry I don't buy that. If that were the case, engine builders would be charging more for 347's than the 393/408's.
Actually, as I mentioned above, the difference in weight of the internals is far from minimal. 10lbs is typical in the cranks, with 8lbs being the least I've seen personally. Now add in a 1500-1600g typical bobweight for the 347, and a 1700-1800g minimum bobweight for the 351, and the distance grows even more. Remember, rotating mass gains weight as it rotates, at an exponential rate. Weight resists acceleration (although it does help make a big power number on a dyno that measures through resistance to deceleration), and acceleration is what moves your car.

Honestly though...all math aside, this is something I can speak of for myself, out of my own personal experience. My 347 powered cars regularly beat on stroker windsor powered cars. My last daily driver, pump gas 347 went 10.70's N/A at 125mph. I put nearly 500 miles a week on that motor for almost 2yrs. My current 347 going in my 67 should eclipse that number pretty easily. Locally, and the Phoenix area is no slouch for fast cars...the only street vehicles that keep up with the 347's are ones with power adders, and I usually have my fun picking on those very power adder guys. No bragging, no patting myself on the back...just honest information.

It's not just about horsepower and torque. There's another factor that way too many people don't take into consideration, and that's acceleration. For me, acceleration is more important than either of the other two. The motors we've dynoed rarely MPH in line with the horsepower they made...they almost ALWAYS MPH higher. That is acceleration, and it's something that a 351 based motor, built the typical way...lacks. Could I build a 408 windsor to beat up on a 347?? Sure I could!! It's not that hard, just uncommon...because it takes more cylinder head, and more cash to do it. You need to get that 408 up in the same rpm range the 347 turns (or usually more to make up for the mass of the rotating assembly) to do it, and most guys that build a windsor stroker are looking for low rpm power and torque. A well built/designed higher rpm 347 has all the advantages in that line up.

Anyway, I'm not trying to be argumentative here at all, just stating my experiences and what I've learned from them, as well as from other builders/racers that I respect. I hope I come across the way I'm intending to!

Cris
 

·
Registered
Joined
·
341 Posts
Discussion Starter #17
Sorry I'm just now getting back to the post. I had to spend a little time on the back of a tow truck. I had a clutch that was on its way out. With the torque my 460 BBC is making, it decided to shorten the install date on the calendar.

http://i120.photobucket.com/albums/o182/agentjdub/towtruck.jpg


One of the reasons I think I keep going back to the 302 is that I have a low rpm, high hp and torque motor already. I want a high revin' one next. I think I'm back on the 5.0L for now. Thanks guys!
 
1 - 17 of 17 Posts
Top