347 STROKER vs JUNKYARD 351W-SBF DYNO DUEL!

[Music] because it's throwback thursday we're going to take a look back at the archives and compare a modified 351 windsor to a modified 347 windsor both of them are equipped with heads cam and intake but prepare to be angry because they're not the same components hey guys richard holden here today we're taking viewer suggestions and i got a lot of comments guys want to see a comparison between a 347 ford and a 350 one ford so which one makes more power so here we go on a reader suggestion guys wanted to see me compare a 351 windsor to a 347 stroker 302 version and honestly this kind of surprises me that people would think that there would be a difference between the two similar displacements because as we've shown in the past on many many videos that when two motors are the same displacement they're going to start out kind of making the same power and as long as we put the same head scan intake and stuff on them they should remain making the same power because primarily that's based on displacement but we'll actually take a look at why we got different results on these two things you guys can yell and scream because i didn't use the same heads cam and intake on both of these combinations but it does show us what happens when we run a similar displacement 351 versus 347 with similar components and what we can expect when we do exactly that so this is our 351 windsor this was a late model hydraulic roller block that i got from the wrecking yard so this thing started out basically as a stock version so we came back and we ran this thing in stock trim the way that we normally do on the engine dyno we ran this with a we took off the efi setup because we were going to run all these test carburetors so installed an elbow performer rpm intake manifold a 750 holley a set of inch and three quarter dyno headers an msd distributor and then we ran it with a missouri electric water pump the way that we run 95 of everything that we run on the dyno so we configured basically in stock trim so we ran it with the stock heads and cam obviously a different intake manifold but the rest of the bottom end was kind of stock so when we ran this thing you know the amazing super powerful 351 windsor in carbureted trim produced a whopping 254 horsepower and torque was up at 352 foot-pounds of torque so not something stellar but what this thing needed because it was suffering basically from a very very mild cam and also very very restrictive factory cylinder heads so what we did was upgrade this back in the day and you can see this i think i have a video up on this upgrade but what we did was put an edelbrock top end package on it now that it'll brock top end package included first of all a very healthy cam shaft it was a 573 582 lift a 235 239 degree duration split so getting up near what might be the limit of available piston to valve clearance and at 112 degree lobe separation angle we also hadn't we installed an air gap rpm air gap edelbrock intake manifold we ran a 750 holley carburetor on this we had the same inch and three quarter dino headers we also put some comp cams roller rockers on this with some one six roller rockers on it and the cylinder heads were a set of edelbrock 185 cnc ported head so they flowed very well and they were sized very well for this particular combination for this 351 especially with this cam and this compression because it still wasn't stellar because that factory uh hydraulic roller combination has a dish piston in it so it was not by any means an ideal combination it was just a junkyard motor that we had upgraded the top end on so after we installed all of that edelbrock stuff the power output jumped dramatically as you can see here 460 horsepower for 59.7 peak torque was up at 435 foot pounds and the interesting thing is and we're going to talk about this just a little bit if you take a look and a lot of guys tend to think oh well with the small heads and the small cam you're going to make a lot of torque that's not true we made a lot more peak torque with a modified combination with the bigger cam and the bigger heads than we did with the stock stuff and although we only ran this down at 3000 rpm if we were to run it even lower than that this modified combination would probably still make more torque than the stock one maybe at a thousand rpm we may see some sort of trade-off but the reality is if you add head flow to it you're usually going to pick up torque and if you compare the stock cam to any kind of performance cam especially a smaller torque kind of cam you're going to pick up power basically just everywhere so there's no the stock that there's no added benefit of that other than possibly you know drivability but this upgrade improved the power output of 351 very well so now let's take a look at what happens when we did a 347 with similar kind of combinations okay guys now we're going to compare the modified 351 to a modified to an equally modified 347 here's where all the apple and orange growers get to jump in and get triggered and get all excited and make comments and i want you guys to do that we're going to talk a little bit after i show you the results here about why this is actually is the same and why it's not different but here's what happened when we ran a 347 and we ran it first the 347 is in red so it stormed out on the big end because you know it's got a shorter stroke and that's not why the difference in power here is this 347 was run with i'll give you a test description here was run with an rpm air gap intake manifold the 750 carburetor it was run with a set of trick flow as cast heads and right off the bat you guys should be making comments right now saying yeah but the edelbrock heads were cnc port and this is an as cast head and i'm going to show you what happens when we run cnc heads on the 347 also but i want to start here we have a hydraulic roller cam 236 248 574 595 lift at 110 degree lobe separation angle different cam similar intake specs more exhaust duration so it's going to tend to want to run higher in the rpm range so what we would expect from the camshaft is more on the top and less on the bottom kind of thing although the 110 should help that out a little bit having a little bit tighter lsa so yes different heads different cam now let's take a look and see what happened when we ran the cnc ported 185 head so similar intake port volume as the edelbrock heads and it did pick up power it picked up power uh went from the as cast heads went from 458 up to 481 peak torque changed a little bit shifted it out a little bit from 419 to 424 so not a big change there as you can see on the 347 the added air flow offered by the cnc heads made itself known past 4 500 rpm and as it went out in rpm it got better and better and where it was able to take advantage of that extra airflow so i'm going to get rid of the ass cast head and we can compare the cnc head on the 347 to the cnc head on the 351 and remember here's where i want you guys to say yeah but they're not the same it's different it's a different cam they're different heads yada yada we are going to take a look here and see what's going on and then we're going to talk a little bit in just a second about what the differences are really between these two motors so we can see that the 347 made more power out of the top and this is kind of something that we would expect from the change in camshaft there's more exaceration than the 351 does the 351 has a little bit more um displacement not a lot a few extra cubic inches but here's something that i do want you to think about and this is one of the differences that we have between these combinations is if you look at a 351 it has a taller deck height so it has a wider intake manifold so it has longer runners so what do longer runners tend to do they tend to make more power down low so on the 351 we have less exhaust cam timing we have a longer intake runner so all of those things are going to tend to push power lower in the rpm range and that's kind of what we're seeing here so we have uh on the 351 we have 460 horsepower versus 480 horsepower for the 347 so you guys can jump up and down yeah 347 for the win short stroke high rpm it makes more power but let's talk a little bit about why there's actually a difference in whether or not it makes a difference so before we get to our take away on what we've learned here let's talk a little bit about i want to know what you guys think the differences are between the 347 and the 351 now why did the 347 make more powers because it's inherently superior and has that short stroke and the big bore we've changed from a 3.5 inch stroke to a 3.4 stroke on the 347 and gone from a four inch board to a 4030 bore you know the big bore so does the big bore and the short stroke inherently make the 347 want to make power at a higher rpm probably not honestly we're not changing things very much i mean if you look at first of all what i want people to do is look at the big picture the big picture is a 347 and a 351 differ by only four cubic inches that's next to nothing but if you multiply that number by whatever the specific output is of the motor you'll see what the potential power difference is if everything else was exactly the same now we did mention a couple of other things if it's not the boren stroke is it the cam timing these cam time these cams are definitely different than these two one has a lot more exhaust duration one has that xfi cabinet the other one has the edelbrock cam in it they have comparable intake directions but they definitely have different valve events so is that can we can we attribute this to the changes in valve events can we attribute this to changes in maybe the cylinder heads they're both 185 cc intake ports they're both cnc ported they both have the same chamber if i remember right and the compressions are the compression on the 351 is actually a little bit less than it is on the 347 so we have a compression difference also but what about the intake manifold as i mentioned the taller deck the wider intake manifold on the 351 is going to tend to want to produce power down low so all of these things contribute to making a difference that we see in the power curves it's not a 347 351 as a matter of fact with either one of those displacements you can make 5 6 7 800 horsepower if you take a look at some of the wilder combinations you can make the power that you want the real question that you need to be asking yourself is not which one makes more power between 347 and 351 they can both make power and they both would make comparable power as we kind of see here with the same combinations the question is what can i fit those in so the shorter deck 351 base 302 will probably fit under the hood of more applications than the larger and taller deck 351. you can make them both the other thing to consider is the 347 is already a stroker version of the 302 so it's already an increased displacement on the 302. now you can with a with the right block you can make a 363 with a 4125 bore and this same stroke and we've seen even bigger versions but it's much more common to make a bigger stroke or out of a 351 you can go to a 383 a 392 or 408 so if you want added torque and added power for a big displacement motor the 351 might be a better choice so those things are much more common questions and in my opinion more important questions than whether ray 351 is better than the 347 because in my mind with comparable things or the same components those two motors are really going to make the same power armature holder make sure to like share subscribe ring the bell do all that stuff make sure to make comments and tell me what i did wrong more testing coming up

Channel: Richard Holdener

Views: 101,699

Rating: 4.9046335 out of 5

Keywords: 347, 351W, DYNO, TEST, WINDSOR, JUNKYARD, HCI

Id: VAi1_2PU-OQ

Length: 12min 15sec (735 seconds)

Published: Thu Mar 11 2021