On this episode of Engine Masters presented by AMSOIL
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00:00 Next time on Engine Masters, we're going to show you how to buy the right cylinder heads.
00:03 Meanwhile, we're going to stumble into a killer combination for a 408 Ford Stroker.
00:09 [ENGINE REVVING]
00:11 This episode is going to be a deep dive on how to buy the right cylinder
00:35 heads for your engine.
00:36 And actually, the data here is being applied to a small block Ford.
00:40 But really, it's kind of broad across any engine family, because all we're dealing
00:44 with here is airflow and the dynamics of the volume and the cross-sectional area
00:49 of the intake port.
00:50 And we're doing that specifically by testing three sets of Airflow Research
00:54 Renegade cylinder heads.
00:56 Now, one of them has 165cc intake port, one of them is a 195cc, and one of them
01:02 is a 220.
01:04 Now, the common internet theory is that you can put too big of a head on your
01:08 engine and therefore lose bottom-end torque, and that's what we want to find
01:12 out.
01:13 And to do that, I've assembled an engine that is a really, really calm,
01:17 street-going motor.
01:19 I wanted to keep the airflow and the RPM down so that we could do the best job
01:24 possible in finding out if too big of an intake port really does kill torque.
01:28 The engine itself is a 410 cubic inch Stroker that's based on a Ford 351
01:33 Windsor.
01:33 The short block is from Blueprint Engines.
01:36 You've seen it a bunch of times on Engine Masters.
01:38 It's been really good to us.
01:39 Up top, the Holley XP carburetor, an 850 double pumper.
01:43 The intake manifold is an Edelbrock dual-plane, best thing for the street,
01:46 best thing for torque.
01:47 It's a Performer RPM air gap.
01:49 We've put MSD ignition in it.
01:51 The cam itself is really small.
01:55 The duration at 50,000th tap at lift is 218 on the intake, 224 on the exhaust,
02:01 very low lift at half an inch, 0.513 inch lift, and it's on 110 degree lobe
02:07 separation angle.
02:08 The engine itself is about 10.2 to 1.
02:10 The exhaust system is a set of open headers, hooker supercomps in a 1 3/4 inch
02:15 tubing diameter.
02:16 What we're going to do with this is run those three sets of heads across it with
02:20 different intake ports, and there's a few other features that they have that are
02:24 different as well, and I'll spell that out later.
02:26 But we're going to start out with the tamest cylinder head that Airflow Research
02:29 makes for the small block Ford.
02:31 It has 165cc intake port, and it's the most affordable one that they make.
02:37 I'm really concerned that it's just going to choke the power out of a big 410 cubic
02:42 inch small block, but you never know until you go strap it on the dyno,
02:45 which is what we're about to do.
02:48 We've run this thing in the dyno in a bunch of different configurations,
02:50 but the one thing that stayed the same is we've always used the AMSOIL Dominator
02:55 1030 in this thing.
02:56 And there's a chance this thing is actually going to squeak its way into one of my
03:00 own cars, and I always use synthetics in the stuff that I really care about,
03:04 obviously not in some of the clapped out junk that I drive.
03:07 So this thing will survive on AMSOIL, and you know I really care about it because,
03:12 look, I brought a funnel so as not to soil my new AFR valve covers.
03:17 ♪ [music] ♪
03:20 Yeah, this is the single smallest camshaft I've ever intentionally installed.
03:26 - So you're turning into me.
03:27 You're turning into a top of the page guy instead of a bottom
03:30 of the page guy.
03:30 - Yeah, smooth idle, nice drivability.
03:34 I still think these cylinder heads are going to strangle it with that
03:36 165cc intake port.
03:38 - I agree.
03:39 - I got to tell you, I got a chance to look at this thing, you know,
03:42 before you guys got here when I was getting it up, and this thing's pretty good.
03:44 I kind of have a new favorite combination, big motors, small heads, small cams, so.
03:49 - It's heresy.
03:52 - I want the small cam and the gigantic head.
03:56 - Yeah.
03:56 - That's going to be the magic.
03:58 ♪ [music] ♪
04:01 - That's ridiculous.
04:26 - In your face.
04:27 - What?
04:28 - That's stupid.
04:29 - That's what I was saying.
04:32 - Wow.
04:32 - I'm like, I'm looking at the curve when I pre-ran it.
04:35 - Yeah.
04:36 - And I'm like, "Oh, wow, would this be fun?"
04:38 I mean, this thing got 450 pound-feet at 2,500 RPM.
04:44 And what was the peak?
04:44 520?
04:45 Let's look at it.
04:46 - Yeah, as far as torque.
04:47 Oh, it's, yeah, it's really...
04:48 - I was just blown away by the torque curve on this thing.
04:52 Look at that.
04:53 We just made 515 pound-feet of torque and 471.4 horsepower.
04:59 I didn't see that coming either.
05:01 - I know.
05:01 That's what I said was so good about it.
05:03 - The 471?
05:04 - Because it's kind of as good power-wise as a good 383 stroke or something,
05:08 but they don't make this kind of torque.
05:10 - They don't, no.
05:10 - And they certainly don't have that kind of drivability.
05:13 - Yeah.
05:14 Now you guys know why I bleed Ford blue, right?
05:18 - Are we only going to ruin it from here?
05:21 - Well, if we take away from here and add to there, then it's kind of driver's
05:25 decision, but as long as we can hold on to this and pick up some of this,
05:29 then that's going to be a win.
05:31 - Can I go out on a limb here?
05:32 - I'm sure you will anyway.
05:35 - I really don't think that the intake port cross-section is going to affect
05:39 that very much, but the increased air flow has got to make it better.
05:42 - Here's the question though.
05:43 What does it do at part throttle?
05:45 We're going to look at full throttle, but what's it do at part throttle with a big,
05:48 big head versus this thing, this 165?
05:51 - Yeah, we don't know.
05:53 Okay, the reason that was mind-blowing is that none of us expected a 410 cubic inch
05:58 engine to be able to make that kind of horsepower and torque through 165cc
06:04 intake port.
06:05 That is considered very small.
06:07 Typically, you'd think of that cylinder head for like a 302 cubic inch engine,
06:12 but I think what that trained us is that that number alone is not everything when
06:16 you're buying a cylinder head, even though it's normally how people refer to heads.
06:20 For example, these would be an AFR 165, 195, and 220.
06:24 That's the lingo that people throw out, but there's more to it.
06:28 Let me explain to you what that CC number really means, and I'm going to do that
06:32 using this cutaway of a Mopar 426 Hemi cylinder head.
06:36 This is actually a Keith Black head that was given to me a long time ago,
06:40 but it's super handy for showing stuff like this.
06:42 So imagine you've got your intake valve right here and your exhaust is over here.
06:47 This is your intake port.
06:48 That's your exhaust port.
06:50 Now, if there was a valve in here sealing it off, and if you were to fill it with
06:54 water up to this face right here, which is where the intake manifold bolts on,
06:58 then you could measure that volume of water in cc's, and it would tell you the
07:02 overall volume of the port.
07:04 That's where those numbers come from.
07:06 But there's another thing that you need to know.
07:08 It's called minimum cross-sectional area.
07:10 It's the smallest point inside the intake port, and it's another number that people
07:15 use to sort of evaluate if a cylinder head is in the range of what they want to use
07:19 or not, and that would be right here on this cylinder head.
07:22 So that changes on the AFR heads as well.
07:25 For example, the 165 cc has a pinch or smallest cross-sectional area of 1.935
07:32 inches.
07:33 Then you move on to your 195, and it's got a 2.075 pinch, and on the biggest head,
07:40 it's actually 2.375.
07:43 So you can see that the size varies a lot, and the theory is that the bigger the
07:48 port is, the more you can tend to lose low RPM torque, and that's what we're going
07:52 to find out today.
07:53 But let me tell you what's the same about the three-cylinder heads that we're going
07:56 to test before I tell you about what's different about them.
07:59 First of all, they're all from Airflow Research.
08:02 They're all from the Renegade line.
08:03 They're all CNC-ported, and they all have a 58 cc chamber on them.
08:08 So the compression ratio on all of these is the same.
08:11 The other thing that's important to note is that the rocker arm studs are in the
08:15 same place on all of these, so you can interchange them without having to worry
08:18 about rocker arm geometry and push rod length and stuff like that.
08:21 Now, here's some things that are different about these cylinder heads.
08:24 The valve size is one of them.
08:25 On the 165 head, you have a 1.94-inch intake valve and a 1.6 in the exhaust.
08:32 The 195 head that we're just about to bolt on has a larger 2.05-inch intake valve and
08:38 a 1.6 in the exhaust.
08:40 And the 220 head, which by the way, this isn't one of them.
08:43 This is just a prop.
08:44 But the 220 has a 2.1-inch intake valve, and because that's so big, they had to reduce
08:50 the size of the exhaust valve to 1.57.
08:54 Another thing that is different between the various heads is going to be the exhaust port.
08:59 They know as the head sort of gets racier and racier that you need more flow not just
09:04 on the intake side, but also on the exhaust.
09:07 And for that reason, the exhaust port is 68cc on the 165, and it's 70 on the other two.
09:13 But the other modification is that the exhaust on the 195 and the 220 is raised, which tends
09:20 to improve flow.
09:22 On the 195cc head, it's raised 0.125 inches, an eighth of an inch.
09:27 On the 220, it's raised 0.375, three-eighths of an inch.
09:32 Now that can be important to you if you're buying headers because sometimes they won't
09:35 fit if the ports have been changed.
09:37 And you can see that on the two bigger cylinder heads, the exhaust pattern is what they call
09:42 double drilled.
09:43 There's a wider pattern and a narrower pattern.
09:46 And especially on the 220, it's possible to put a header on it that can block a little
09:50 bit of that exhaust port flow.
09:52 So what we're doing here is not just scientifically testing the intake port design alone.
09:58 Instead, we're going to test what you can realistically buy off the shelf from any manufacturer
10:03 for any domestic V8 engine that you might have.
10:06 Because this technology, it all applies to anything, a Chevy, a Mopar, whatever.
10:10 And we're going to do the best to sort of bench race that out and get some solid data
10:14 when we go to the dyno and remove the 165 to install the 195cc head as our next step
10:22 and finally we're going to wrap it up with the AFR 220 and find out if, like the internet
10:27 says, too big of a head can kill torque.
10:30 I've got a really simple theory when it comes to heads, port size, velocity and all that.
10:38 Bigger is better?
10:39 Oh man, you just totally stole my thunder.
10:42 How did you know?
10:44 I've met you.
10:45 I think here's a good tech note.
10:56 Because on some of the gasket manufacturers you'll see on the Ford gas that says front,
11:02 this one actually doesn't.
11:04 So you need to be smart enough to know why.
11:07 In both the cylinder head and the block, there are water passages.
11:10 It's the head gasket that determines the direction of flow.
11:13 So if we were to have put this gasket on this way, the water is going to enter the water
11:20 pump, come through the cylinder head, come right out here into the intake manifold and
11:24 back out the front.
11:25 This whole part of the motor would have zero flow.
11:28 I did not know.
11:29 So now we do this and the water is forced all the way to the back, comes up the back,
11:35 through the head, out the water passage so it circulates and flows and cools the whole
11:39 block.
11:40 Also did you notice this is a Mr. Gasket MLS?
11:42 I did.
11:43 Their claim is that the coating on this does not require as smooth a surface as some of
11:47 the other ones.
11:48 Oh interesting because you have a lot of them that give you a specific RA finish that you
11:52 have to have to use the gasket.
11:53 They say it can be a little bit rougher.
11:56 Just so you know that's my one and only Ford tech tip for the year.
11:58 It was really good.
11:59 I liked it.
12:00 I only have two.
12:01 I'll save one for next year.
12:03 195 cylinder heads going on.
12:06 Here comes a winner.
12:07 You know what else is really cool about the AFR head?
12:10 What?
12:11 8mm valve stem.
12:12 Oh that's really good.
12:14 Kills some weight, flows better.
12:27 I'm confident it makes more power everywhere.
12:29 That would be cool if it did because it made really good power before.
12:32 We have a pretty big step to go up.
12:35 It flows a lot more.
12:36 But the valve diameter is good on this head.
12:39 I like that.
12:40 Will it make 500 horsepower?
12:41 Are we going to pick up 30 numbers?
12:43 No.
12:44 I don't think so either.
12:45 Well, blurt out a number, Steve-O.
12:46 Come on.
12:47 93.
12:48 93?
12:49 493 horsepower.
12:50 Well, we were at 470, right?
12:53 Yeah.
12:54 500.
12:55 Dulcich called it.
12:57 I can't nay say it because he's Dulcich.
13:00 I know.
13:01 The wizard of all wizards.
13:20 Not quite there, but still really impressive.
13:22 I had a pretty good feeling when it came in about 8 pound feet better.
13:27 So at this point, with this cam, so far, this is a better cylinder head.
13:31 Absolutely.
13:32 The bigger cylinder head makes more power.
13:34 Kind of no shock whatsoever.
13:36 Really at every single point in the curve.
13:38 This stuff down here is like 2,600 and below, and it's the same down there.
13:43 So we made 520.8 pound feet of torque, 484 horsepower, with a really broad spread.
13:50 Almost 1,800 RPM between the RPM at peak torque and peak horsepower, which makes for a really
13:56 nice engine.
13:57 You know, I don't think the big surprise is the 195.
13:59 I think the big surprise is how good the 165 is.
14:03 It's amazing.
14:04 It still blows my mind.
14:05 I'm really shocked by it.
14:06 The thing we don't know is throttle response, transitional throttle, part throttle.
14:12 We know the airspeed has got to be faster through the 165 head, and we know that that
14:16 leads to better tipping.
14:17 I know with the 165, it would be really good.
14:20 What?
14:21 The part throttle, transitional throttle response, all that stuff, it would be really good.
14:25 And on this big of an engine, even the 195, it's got to be excellent.
14:28 It's got to be.
14:29 But now, is the 220 going to finally lose some torque, or are we going to see the same
14:34 torque and even more power?
14:35 I say same torque and more power.
14:43 I think every internet forum on earth claims this is going to be worse, killing torque,
14:49 right?
14:50 Really?
14:51 Yeah, I think they do.
14:52 I don't read the internet enough, apparently.
14:53 It would be consensus.
14:55 Consensus would be it's too big.
14:57 Yeah, too big of a port.
14:58 It's just like Goldilocks and the three bears.
15:01 The other heads are probably just right.
15:03 Yeah, probably.
15:04 But probably not.
15:05 I'd say Papa Bear is the best.
15:07 The fail in our test here is I think I chose a 410 cubic inch engine.
15:12 Had you chosen a 302 and started with a 165 and found out that a 220 might be too big
15:18 at some point?
15:19 I tried to compensate for that with a small camshaft.
15:22 And then you just made more torque.
15:23 All I did is make more torque.
15:25 How are we going to live with ourselves if it actually makes more power everywhere?
15:28 I think it will.
15:29 People tell us we're wrong.
15:30 I think it will.
15:31 I really do.
15:32 I think it will too.
15:34 It might give up a little bit of torque.
15:35 It might give up 5 or 6 between 2500 and 3 is my guess.
15:39 And then it's off to the races.
15:41 And it's going to make 497 horsepower.
15:43 493.
15:44 493?
15:45 I don't want to make a guess this time.
15:48 I'm going to guess because it doesn't matter.
15:49 You're always right and I'm always wrong.
15:52 I'm just going to be silent on this one.
15:54 Okay.
15:55 Let's find out what it is going to do.
16:22 The same as the 165?
16:23 Yeah.
16:24 After all of that, I'm not sure we really proved anything.
16:27 You proved I don't know anything.
16:28 I know.
16:29 I don't know anything either.
16:30 I mean, I proved, I think, that that 165 is a killer head.
16:34 I think we proved the 195 is the logical one.
16:36 You really should run on an engine like this, even if you've got another 20 degrees of cam
16:39 probably.
16:40 And if it's anything bigger than that, you want the 220 with the correct single plane
16:44 intake manifold and the correct solid roller cam and the correct big header.
16:48 And making peak power at 7500 RPM.
16:51 All of those things that that head is designed for with that kind of flow number at 800 lift.
16:55 This is the craziest thing.
16:57 These numbers we have on the screen right now, those are the 165 head versus the 220.
17:03 They essentially run exactly the same.
17:05 So my walk away is throw the 195s back on this thing and stab it in the Mach 1 and have
17:09 a great time.
17:10 Ready to go wrap this up and try and package all this information into a believable ball
17:15 of BS.
17:16 Oh no.
17:17 Believable or unbelievable, the numbers are the numbers.
17:19 They're just a little confusing even from now.
17:21 I've got it all put in a box, man.
17:23 I get it completely.
17:25 Well go spill.
17:26 Let's do it.
17:31 Okay Steve, open up your big box of wisdom.
17:34 Well I've got to admit, I mean, the 408 Ford took me to school.
17:37 Really?
17:38 Yeah.
17:39 My whole theory of bigger is always better kind of let me down for the first time.
17:43 So what's the point, Dulcich?
17:45 Well the point as far as I'm concerned is we didn't lose any low end torque and that's
17:49 really what people talk about with bigger heads.
17:52 We made great power with a tiny head on a big cubic inch motor with a tiny camshaft.
17:57 So I guess really there is no conclusion.
18:01 Well no, there is because of what you're talking about.
18:03 I think that we are starting to see stuff that we've never tested before where a good
18:08 cylinder head with a tiny camshaft is a great street motor and that's probably something
18:12 a lot of people have known for a long time but we're just discovering it because normally
18:15 we like giant cam stuff.
18:17 But the whole thing about proving that a large port kills low end torque, we didn't see that
18:23 at all.
18:25 But to be fair, on the dyno it's not really showing throttle transitions and things like
18:30 that.
18:31 So I'm not sure that people can conclude categorically that you should always put the biggest cylinder
18:34 head that you can on your engine.
18:36 I don't think that's the case.
18:37 I think the 195 is the right cylinder head for this combination.
18:41 You took the words right out of my mouth.
18:42 I was going to say, the 195 seemed to be the optimum.
18:45 It did make the most horsepower and it's probably the right head for this motor.
18:48 So you were going to open your big box of wisdom and I just ripped it open like a five
18:53 year old on Christmas morning?
18:54 I've already shared with you all the conclusions.
18:56 Oh that's right, I just sapped your knowledge and shared it with the audience as if it was
19:00 mine.
19:01 And that's what happens pretty much on every episode of Engine Masters.
19:05 We'll see you next time.
19:06 This is not a man bun, is it?
19:14 Well not yet.
19:15 No, it never will be.
19:17 If you move it just an inch higher you're getting close to a man bun.
19:20 It's a ponytail now.
19:21 It's a ponytail.
19:22 It's a ponytail.
19:23 It's a ponytail.
19:23 (explosion)
19:26 [BLANK_AUDIO]