Can David Vizard Win My 538 Camshaft Challenge? #mopar #engine #dyno

Added: 2026-05-23

[00:00:00]All right, Mopar people. Welcome back to the channel. I'm just Mopar Joe. I'm doing my very best to do something for the Mopar engine lovers out there. This year, I'm having a 538 cam shaft shootout. Right now, I have talked to Brian Salter of Salter Racing Engines.

[00:00:18]He's on YouTube. Um, today's conversation will be with David Visard of David Visard. He does Power Tech 10 series. Um, he's been out there a long time. Uh, British engineer, pretty well accomplished guy, knows a lot about engines, theory, cam shafts. He has a program, cam shaft program that he's very proud of, and we're going to use that program in today's video to do an initial spec of what we need for our 538 engine. I'm going to go over those engine specs with David in the video.

[00:00:53]David's going to show how this program works and then we're going to end up we can end this video with our leadup to part two on what's actually going to happen. We we're kind of stuck between two cams and your input is always welcomed. I I read all my comments. Uh but look forward to our cam shaft uh shootout this year. They'll be swapped out on the dyno just like Eric Wegartner is doing at Coun. I'll be at Coun on their new dyno. Uh, and we're going to get a lot of information. So, our third contestant will be Daniel Pal of Pal Machine, also on YouTube, and I'll have an interview with him coming up soon.

[00:01:31]Hopefully, you'll enjoy this. Let's get into it. Well, let me just say for your the benefit of your viewers that I'm very, how shall I say flattered that you made room in your competition after technically it was closed for me to have a go at this.

[00:01:53]Right. So, and young Daniel, the cam shaft company said he would grind the cam for me at his expense. So, I I'm kind of indebted to you guys. So, thank you very much for that. I very much appreciate that, Joe.

[00:02:11]I've been meaning to get to the >> calculations for this, but tell the viewers what it is we're dealing with exactly. Right. But all I know is it's a big big block Mopar.

[00:02:25]>> So it it's it's kind of an interesting um mixture of components here. So we have uh we start with a stock 440 block which would be the RB raised deck block.

[00:02:38]Um the owner of this car engine project etc. He's got a 72 Plymouth Cuda. He wants this engine, it's its design destination is to be a drag and drive car. Um, he was dead set on having a four and a half inch stroke crankshaft in this engine. Uh, we're looking at 4340 bore or four, excuse me, 4360 bore.

[00:03:02]So, it's actually uh more stroke than we have bore size. And I I feel like that's going to be a challenge because he wants to turn 6,500 RPM.

[00:03:12]And >> what's the piston speed at that?

[00:03:16]>> I'm honestly not sure. Uh it's a 7100 rods >> in it.

[00:03:21]>> Yes, sir. U right now we have a Molar uh excuse me, we have a >> Calli's Compstar crankshaft Molar rods >> and we're looking at I believe Wiseco pistons now. So Daniel's Daniel's ordering our pistons. He has our heads.

[00:03:36]These are Trick Flow 270 heads uh that were reported by Charles Cervidio. I know >> Charlie. Good old Charlie.

[00:03:46]>> Yes, sir. He's He's a He's a student of yours.

[00:03:50]>> He's also a lot of fun to be around.

[00:03:53]>> Yes, sir. He He's done extensive work to those and to the intake. So, our intake, we have a single plane. It's a 4150 intake. Uh, and that's that's part of our challenge with this is that the owner wants this to fit under his flat hood of this 72 Cuda.

[00:04:10]>> Yep.

[00:04:10]>> So, we we really can't we're kind of limited by we can't stack twoinch spacers. He he doesn't have really room for a dominator. I know you and I spoke about that before and even with testing, maybe we could slip one on, but at the end of the day, it has to run with those constraints.

[00:04:27]>> Can I ask a question here, Joe?

[00:04:30]>> Yes, sir.

[00:04:31]any possibility that we could do our dyno testing on a 4500 carburetor and a spacer because that engine is going to I mean big inches and some good heads.

[00:04:44]It's going to absolutely suck the inards out of a 4150 carburetor. You know, we'll find parts in the cylinders, right?

[00:04:56]So, what's the chances of doing the testing on a 4500 car?

[00:05:02]>> I'm I'm certain I may can find one. I know I have an adapter uh like an HVH Super Sucker adapter that that would go for the tapered four hole spacer into a 4150. That would be our the easy choice of just bolting that on.

[00:05:17]>> Yeah.

[00:05:17]>> Try try to go. would estimate we really for this engine we really need something a minimum of 1250 and I would think 1350 might be nearer end right I mean I know Charlie's going to do a good job with the head >> right you've only got one you've got a problem >> well I say I have his flow numbers I think our max flow right now is 371 at 700 lift Yeah.

[00:05:48]>> And >> well, there's enough power there that uh there's enough power potential there for it to pretty much demand a 4500 series carver rotor.

[00:06:00]>> I know the the owner is is very set on wanting to spend RPM. He wants 6,500 plus, but >> Well, we'll we'll see. You know, uh we could work out the uh piston speed uh Yes, sir.

[00:06:15]>> with my program. Let me let me just do that.

[00:06:23]Yeah. You know, a as you've just pointed out, the piston speed is going to be up there. 6,500 RPM. And what was the stroke again? Four and a half.

[00:06:34]>> Four. Four and a half inch.

[00:06:36]>> Yeah. I mean, it's possible, but he better have the very best stuff.

[00:06:41]>> Yes, sir. I mean, I know John Kazzy has built 4 and a half inch stroke engines that he's turned 8,000.

[00:06:52]But some of them even more than that. I mean, but John's got the world record for piston speed. Did you know that?

[00:07:01]>> I did not know that.

[00:07:02]>> No. His engines have more piston speed than even the highest RPM Formula 1 engines.

[00:07:09]>> Wow.

[00:07:10]>> Right. Yeah. Yeah. and they live, but for a drag strip, right? Not certainly not a road car and a drag car. So, I think uh your guy is going to be RPM limited.

[00:07:28]So, what do we make the cam for? 6500.

[00:07:33]>> That's that's the goal. And I I would think for our testing, it's going to have so much torque typically.

[00:07:40]Uh, and I, you know, when I dyno test at Coons, they have, they have an issue pulling, you know, below 3,800. The dyno just is loaded up. It, it can't read torque after a certain point because >> it's a baby one.

[00:07:54]>> Well, the, you know, the the previous I think my previous engine there was making over 800 foot-lbs uh, and it carried it for >> 1500.

[00:08:06]>> Yes, sir.

[00:08:07]>> Yeah. Yeah. when when you get to those very big torque numbers, you need two absorbers on it, right? I I was lucky when uh when I ran out of capacity on my Superflow and I had a special big absorber on it. I had a friend who had an Aero Dynino, right? This sucker had a 19inch absorber compared with Super 5 in and the absorber impeller weighed 90 pounds.

[00:08:35]>> Wow.

[00:08:36]>> Right. And it would pull down a pretty big aero engine making maybe 5,000 footbs down to,000 RPM.

[00:08:53]>> Mhm.

[00:08:54]>> I put my big block on it and I could pull it down to stall it. Right. And this was a nearly 2,000 horsepower big block. So, it did the job, right? I I know they're they they've upgraded and built a new room with a new dyno there and that's what Eric Wegartner's using trying to use for his current cam shaft challenge.

[00:09:16]>> Now, I did have a question here.

[00:09:19]Everybody else has got their entry in, right?

[00:09:23]>> Uh so far, uh Brian's came as ground.

[00:09:26]Daniel is working on his now.

[00:09:28]>> Uh so, we really should get mine sorted out and then you can communicate with him. What I'm going to do is use my big block Chevy program to calculate what the cam event events should be. Uh there's no initial input on the valve events at all. I mean, you'll get some people, they will say, "Well, I calculate my cam, right?" Uh, and uh, and I start with deciding where I'm going to close the intake valve. Well, you didn't calculate that. You guessed it.

[00:10:12]>> Mhm.

[00:10:13]>> I don't do that. I start with a blank piece of paper and the engine tells me what it wants. I don't tell it.

[00:10:22]Now, here's something that a lot of people don't realize. The nearer your cam is to being right in terms of its opening and closing points and the the ratios between us, that's the lobe center line angle. The nearer the lobe center line angle is to optimum, the more fussy the timing is. And I and this is how I explain it to people. If you've got your cam lobe center line off, say it's too wide. When you advance the cam, the intake uh uh function may get better, but the exhaust will get worse and they kind of cancel each other out.

[00:11:00]And when you it, the exhaust function may get better and the intake worse. So, and I've had people say, "Well, it doesn't seem to be too fussy about the timing because the power goes up and then it hangs like this and it goes down." Now, if you've got it right, when you advance the the cam, both intake and exhaust are wrong. When you retire it, both intake and exhaust are wrong. So, now your power curve goes like that. There's the optimum. You've got almost no margin for error.

[00:11:35]And I'm I'm gonna I'm imagining here with with this big engine that we what we have here is something where as good as Charlie is, there's never enough flow.

[00:11:49]>> Right.

[00:11:50]>> Right. So, we've got to make use of every single CFM at every part of that opening phase and closing phase and put it in the right place. So getting the cam right on the lobe center line angle and then timing it in right could be the last 25 horsepower which you didn't get by and if the lobe center line angle is wrong you could be 50 horsepower off.

[00:12:18]>> Wow. A big consideration for me is like longevity of this engine because I have to put my name on it. So, is there a way that we decide?

[00:12:27]>> Yeah, we limit the RPM because that's what kills them.

[00:12:30]>> That Yes, sir. But I mean, even like lobe intensity, if if this lobe just if it rushes on very quickly and it's it's jamming this valve open and closed over and over.

[00:12:41]>> Yeah, we'll we'll talk to Daniel about that. Who's the other cams?

[00:12:47]>> Uh Brian Salter of Salter Racing, >> right? Uh has he put his cam in yet?

[00:12:54]Yes, sir. So, his cam is ground. I don't have it yet, and I I don't know the specs on it. I only know we were going around 750 lift, >> right? Uh, >> and >> what springs have you got on the heads?

[00:13:09]>> Daniel is specking the springs. We We have a set of springs now. I believe they're pack springs. Uh, but they're uh they're not the end all beall. So, we we kind of bought springs early. I want I kind of wanted to wait. Um, so we're we're looking at buying a different set.

[00:13:26]>> And I think PAC makes these springs, but I know they made some springs for me oh, five or six years ago for a uh um a vintage racing 289 Mustang. It was a single coil spring, right? And the poundage on the seat and over the nose were lower than a stock spring.

[00:13:54]>> Yep.

[00:13:55]>> Wow.

[00:13:56]>> And this cam which lifted the valves ion 600 would turn 8,000 RPM just like that.

[00:14:07]Um now what manifold are you using on this?

[00:14:10]>> Uh this is a Mopar M1. So it's it's the special one that can fit under that flat hood. It's a single plane.

[00:14:20]I know that's pretty crude. Can you see there?

[00:14:23]>> Uh, yes. And it wants one of my humps in the middle. Right.

[00:14:29]Um, right. Uh, let me uh >> I'll send you I'll send you a sketch as to what it should be like. Right. Uh, it looks pretty good. Is this one you've done?

[00:14:43]>> No, Charlie did this one. So, there's >> Charlie did it right. Okay. I should have guessed that was his work. It's all uh his cuttering works very good, isn't it?

[00:14:54]>> Yes, sir.

[00:14:55]>> It looks like he's almost machine guided. Um >> and those are those are the Mopar Max wedge ports. So, he's he's port matched as close as he could >> without actually having an engine block there. So he said I may need to adjust some of the the floor the the roof of the port.

[00:15:17]>> We're doing a big block Mopar.

[00:15:19]Fortunately, I found an easy route to change some of the constants to get this program to calculate the lobe center line angle, the big block mopar because the uh geometry is quite different and the gas transfer across TDC with the parallel valve head versus an incline valve head is substantially different.

[00:15:48]Anyway, when we get to that difference, I'll let you know. But what we start off with is we enter the bore 4.36, then the stroke 4.5.

[00:16:00]Rod center to center length 7.1.

[00:16:04]Intake valve diameter a woefully small 2.19.

[00:16:10]Exhaust valve diameter still way on the small side for such a big engine, but it's a 1.81. 81.

[00:16:18]Part of the saving grace of this engine that it's got a fairly high compression.

[00:16:23]And there's an old saying that if you don't fill the cylinder very well, you better squeeze what you've got in there pretty hard. Very sound saying. Now, we want peak power at 6,500.

[00:16:36]Now, that I want to stress here that we want the power at 6,500.

[00:16:42]Now, we're going to find that this program will show us what shortcomings we may have to meet our goal. Red numbers in the yellow boxes are the result of a calculation of calculating the data. But, and I've already taken the liberty of calculating it, but going on down, we put the rocker ratios in 1.6 1.6. And we want a cam for mid to top end. So, we're going to need a dual pattern cam. So, we put a one in. Then, we go across to the calculate data.

[00:17:18]Boom. Hit that button and it calculates all the data that you will need for a cam selection. Now, let's go across to that column. That's the one to the right of the column we've just uh entered the data into. And we will see that it's quoting a lobe center line angle of 106.

[00:17:41]Well, that would be right for a big block Chevy, but as it happens for the big block Mopar, it needs to be 3° tighter than that. So, our lobe center line angle or lobe separation angle, call it what you will, is going to be 103, not 106. Now, the 20,000 duration intake 296.

[00:18:07]The 20,000 degree exhaust 309. Now, I know somebody's going to say, "Well, wouldn't the 50,000 number be more applicable?" Well, yes, but it's more convenient to calculate the duration at 20,000 first and then you've got the option of deciding how fast to open the valves. And we do that in the next section. overlap 90 and a half degrees advance 4.6. This is a calculated advance. It's not the almost obligatory four degree advance. This actually takes into account, the valve sizes and where they need to be in relation to the crankshaft in the opening phase of the valve train. The intake center line is at 4.6 advance is going to be 101.4.

[00:18:59]Now here we come to one of our first problems. Recommended minimum intake valve lift 988.

[00:19:08]Recommended minimum exhaust valve lift 948,000.

[00:19:13]Well, between you and me, we aren't going to be able to get that. And it wouldn't be any good anyway. It'd be way past the peak flow lift of the head we're using. What we do have is a 750 valve lift limit. So, something's got to be done about that. But let's move on.

[00:19:35]The dynamic compression ratio 8.5 for a street strip motor, which I've is what I've chosen here.

[00:19:45]Uh that's about as low as we want to let it go. We we would like to see it nearer 9:1 in this particular instance.

[00:19:56]Cranking cylinder pressure PSI 221 780 lb feet. Estimated power potential 872.

[00:20:09]Oh, this does look really good here, but there's a snag.

[00:20:13]Right below that estimated power, it tells you what the recommended minimum CFM head port flow is. To get that 872 horsepower, we're going to need 426 CFM of flow. We don't have that. We have about 380.

[00:20:33]So, we aren't going to make that 872.

[00:20:38]Uh quick quick calculation here off the top of my head. We're going to be about 100 horsepower shy of that 872. So if we've got everything working well, 772 should be about where we could get to if everything was spot on. Redundant for what we're doing. The only thing that I can say is Charlie Cvido has done the heads and he's one of those head porters that doesn't make the ports any bigger than they need to be. So we can pretty much assume that that port area for the heads is about right. Next we come to the intake length in inches. This is from the center of the valve right through to the center of the port where it enters the plenum. I provisionally put in 11.5 there. I don't know what it actually is, but that's what I've entered. The wave reflection. That's the second, third, or fourth wave reflection. the fourth one.

[00:21:36]Right now then we've got all that in.

[00:21:40]Now we go over and look at what snags we've got.

[00:21:47]As you can see, the 6,500 RPM limit is giving us a piston speed of 4,875T per minute. That's a little bit over our speed limit. I dare say that for brief moments and not too regular use of that 6,500, the parts are good enough to hold hold everything together. But nonetheless, we ought to look at putting that figured peak power down slightly. So we'll consider that in a moment. Now let's go and look at the other factors. Here we have um the vacuum at idle which very few other cam programs ever tell you. In fact, very few actually tell you all this data. Vacuum at idle assuming it all sealing up properly. 6.7 in of mercury. Not good. I think what we need to do here is to maybe look at a lower RPM. Instead of quoting peak power at 6,500, let's make it 6,000 and see where we get to then to the 6,000 RPM mark. So, let's move along the line here and see what it's changed.

[00:23:12]After we hit the calculate button, we go across to the next column as we had before. Still on 106 slope center line angle, but the cam duration has dropped 287 297. And you can see as we go down the list, things have perked up in the civility area. We've now calling for 925 lift and 888. It's a bit less. We have 9.6 for our vacuum. And if we go on across the page, we've now got a dynamic compression ratio of 8.8.

[00:23:55]The next subject on the list is the cranking pressure. Now, this is 234 PSI.

[00:24:04]That's getting a bit high for 93 octane fuel. And my guess is that it will probably, but not certainly need an octane booster. Now, that will all depend on how good our mixture atomization is and what the mixture ratio is, etc. A lot of things. Maybe just about doable, but my guess is probably not so much. Anyway, let's go on down the list. Horsepower and torque.

[00:24:38]Look at this.

[00:24:40]783 foot-lb. We've actually gone up a couple of footbs on torque. However, our expected horsepower has dropped by oh, I don't know about 50 horsepower at 818.

[00:24:55]Now, those figures are nice, but let's have a look at our required CFM of port flow. 401 CFM. still higher than we've got. But dare we put anything in that's less duration than this because our cranking pressure will go up skyhigh.

[00:25:17]So let's see what we should do here.

[00:25:20]Let's stick at the 401 uh CFM requirement even though we've only got about 380. Now, induction length in this instance, we go to 12.3 in in length for the intake.

[00:25:36]With the fourth reflection, that will give us peak horsepower RPM of 6,16.

[00:25:44]Well, that's close enough to 6,000.

[00:25:46]And our torque will be about 4,700 RPM peak. So, fairly good numbers.

[00:25:55]That's where we would kind of expect it.

[00:25:58]>> So, basically, we have two options.

[00:26:02]He can do the cam with a 6,000 RPM peak.

[00:26:06]That would give some different variations of numbers or we can do the bigger one trying to go for 6,500, but the program already shows us that, and we kind of knew it anyway. Um, we're lacking head flow here.

[00:26:19]The deal is have a cam ground that works with a constraint of the parts that we're using. Um, this is going under a flat hood in the CUDA. So, that's why we're using that 337 intake. We're not we didn't want to step up to Brodics or any any stuff like that. It's a drag and drive deal. So, we're trying to use appropriate parts.

[00:26:45]And again, the owner uh wanted the larger cubic inch. I would have probably chosen something smaller to kind of match the head flow better, but um he was ready to go big or go home. So stay tuned for part two from David. Um I got Daniel coming up next before you know it. So thank y'all for watching and we're going to have some dino time before you know it. Also, don't forget about our 526 back here. All right, bar people.