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5.9 Magnum cam specs

74Runneer

74Runneer

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I called up both Crane and Comp today to see what their recommendations were for a cam for my 5.9 build. Stock bottom end, stock heads, air gap intake, headers, dual exhaust, FBO ignition, and an eddy 1406 carb 600 cfm (might upgrade this), 3.23 gears, street strip use. I want the long snout with a mechanical fuel pump eccentric on it. Stock heads flow about 190-200 cfm with 1.92 valves. This is a very mild build just to get me through the next 2-4 years and hopefully by that time my drivetrain will be able to handle more power (8 3/4), then comes the 408 stroker with decent heads...

Anyways, I gave them that information and comp recommended this cam:
COMP Cams 20-614-9
  • Lift: .480"/.480"
  • Duration @ .050: 210°/220°
  • Lobe Separation Angle: 112°

And Crane recommended this:
Custom grind
Lift: .531"/.552"
Duration @ .050: 220/226
LSA: 110

I would obviously get the springs that they recommend.

Anyone have any experience with these cams? The comp stick seems too tame to me, but I also dont want to have drivability issues.
 
My 2 cents. Mild build and the Crane cam do not match. Not if you are looking for drive ability.
 
Whew! That’s a tough one because I used a cam that speced in between the two. I used a Crane cam. IIRC, the duration @.050 on the Hyd flat tappet I used were 218/224-.454/.480-112 which worked really well with the 25-1/2 tires & 3.21 gears I had. I don’t know if I’d go up to 220*’s & a stock converter. With variable duration lifters, it would be super flexible.

The Comp Cam is more street friendly.

Check retainer clearances with the Crane.
 
You’ll have similar but better performance than I had in my mill. IMO, your going to like it a lot. Power starts just off idle and will go very well to 5500 no problem.
 
go to Mike Jones Jones cams website and fill out the cam request card then get whatever he recommends
his inverse radius profiles are much superior to anything else out there
 
IIRC, the normally accepted max lift on stock Mag heads is about .520

I'd not risk the post #4 cam without guide work.

There are a couple of off the shelf long snout roller cams with .512 and .517 (@ 1.6 rocker ratio) lift that would eliminate that head work.
 
Hughes says that cam is for the stock magnum head as long as you use their springs and retainers.
 
Stock 360 has probably under 8-1 actual compression ratio. That coupled with the 3.23 l'd use the smaller cam.
Doug
 
It's a magnum 5.9 with 60-62cc heads so the stock compression was 9.1:1, but seems like most are closer to 8.7:1. But I would think with a thin head gasket I could get close to 9:1
 
Wow!

Did anybody actually measure the parts needed to find the actual ratio or are we just talking about what we heard/read last?

The Hughesengines retainers are a trick part.
 
Well 9.1:1 is the published number. I pick the engine up at the end of the week. I'll get the head magnafluxed and measure piston deck height as well. The CR won't be below 8:1.
 
I was pretty certain the 5.9 was an 8.8:1 motor and the claim was that it didn't need premium fuel.

That 8.8 should be a lot closer to the actual number as they got a lot better in truthfulness over time.

I'd also like to see the official numbers as I found it odd that an LA roller 5.2 is a 9.2:1 engine, but the Magnums were lower.
 
Yeah I've searched all over but it seems like everyone says they are between 8.8:1 and 9.2:1, but I haven't found any official numbers. The 11.25 cc dish pistons dont help the CR much, but doing the math, the CR fit in between the range above depending on how far the piston sits in the hole. I'll measure mine and if it's too far down then I'll use a 0.028" compressed thickness head gasket to bump it up.
 
do the math and post back
cr does help determine fine tune cam choice especially with tall gears and wide ratio AT
 
I finally got around to figuring out my build. I ended up going with Hughes EQ Iron Ram heads with their spring and retainer kit and their 214/218 steamroller cam. The compression ratio of my engine was 9.06:1 using a 0.028" compressed thickness head gasket. To my surprise, my pistons were not the stock units, they were actually a sealed power hypereutectic piston with a smaller dish but a lower compression height. These sealed power slugs were 0.085 in the hole.
 
I have a very similar build and am considering the Hughes cam as well. I am also considering the Lunati 20200715 (264/270, 213/219. 485/485,112) and the Comp 264HR-12 (264/274, 210/220, 480/480, 112).
I emailed my set-up to Jones but haven't heard back. Same with Howards. Oregon has been helpful but I need to give them my updated spring (Hughes 1119) info.

Keep us posted Runner.

Are the heads large or small valve version?
 
I ended up going with the standard sized valves. I had to draw the line somewhere, if I upgraded valves, then I would have wanted to upgrade rockers, guide plates, and push rods. If I did that then I would have wanted higher comp pistons with a bigger cam. At that point, I might as well get aluminum heads. And on and on and on.... I'll keep you posted on how things go.
 
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