.474 Big Block Mopar Performance Cam Specs

[John Milner]

Has anyone actually measured the P4452993 Mopar Performance big block camshaft to see what the duration specs actually are @.050? The duration shows to be 238/[email protected]. I currently run the 268/284 .450/.458 Mopar Performance magnum restoration cam and the @.050 specs were clearly way off on that one. I'm assuming that the @.050 specs on the .474 cam are off as well. I'm considering running this cam in a 9.5:1 440.

 

[furious70]

I didn't think there were any published .050 specs for any purple shaft?

 

[Kern Dog]

Hey John.
I had that cam in my first 440.
It ran quite good and had great street manners.

 

[lewtot184]

I measured one a few years back and they're not exactly as advertised. I didn’t keep notes on it but thinking .050 number was in the low 230's. Seat timing shocked me. If I remember correctly the cam was around [email protected]", and the 280 number was around .008". Pretty sure it's just a generic profile that can be had from speed pro or sealed power and can be had for chevys, Ford or whatever. I don't think it's bad but doubt there's anything mopar special about the lobe profile.

 

[Geoff 2]

It was 238/238 @ 050.

 

[John Milner]

Hey John.
I had that cam in my first 440.
It ran quite good and had great street manners.

Hi Greg - That is great to know. What compression ratio did you run in your first 440?

 

[Kern Dog]

My first was a stock bore 440 from a 78 New Yorker. I milled the heads .050 and the heads .010 as directed by Mopar Muscle. Back in the late 90s, early 2000s they had a lot of tech questions about how to spice up a low mile 440. Their tech Q & A section was supposedly written by Dick Landy but it was alleged that it was actually someone else. The milling was supposed to raise the compression 1 point from the 8.2 ratio to 9.2. I never checked the depth the pistons were in the hole so I cannot verify that.

 

[PRHeads]

Has anyone actually measured the P3690933 Mopar Performance big block camshaft to see what the duration specs actually are @.050?

Part number P3690933 is a valve spring.

The BB 474 cam is number P4452993.

It’s going to be noticeably hotter than the stock 375hp grind, especially if you have a better intake, headers, and some head work done.
It’s not that much different than a Comp 280H.

Comp has a version of the 474 cam, as well as Mancini.

 

[Kern Dog]

My Charger ran a 14.01 at 101 with a pathetic 2.20 60' time with the first 440 and 3.91 gears. I had heavy wheel spin through 1st gear. I had street tires and limited traction due to my limited skills. I probably gave up 3 tenths to just the crappy start.

 

[John Milner]

Part number P3690933 is a valve spring.

The BB 474 cam is number P4452993.

It’s going to be noticeably hotter than the stock 375hp grind, especially if you have a better intake, headers, and some head work done.
It’s not that much different than a Comp 280H.

Comp has a version of the 474 cam, as well as Mancini.

Thanks for catching that. I modified my post with the correct number. I also appreciate your input on the cam. That is good to hear.

 

[John Milner]

My Charger ran a 14.01 at 101 with a pathetic 2.20 60' time with the first 440 and 3.91 gears. I had heavy wheel spin through 1st gear. I had street tires and limited traction due to my limited skills. I probably gave up 3 tenths to just the crappy start.

Sounds like it ran very well. That is exactly what I am looking for with this particular engine.

 

[BSB67]

Has anyone actually measured the P4452993 Mopar Performance big block camshaft to see what the duration specs actually are @.050? The duration shows to be 238/[email protected]. I currently run the 268/284 .450/.458 Mopar Performance magnum restoration cam and the @.050 specs were clearly way off on that one. I'm assuming that the @.050 specs on the .474 cam are off as well. I'm considering running this cam in a 9.5:1 440.

Yes. It measures 234 @ 0.050". The 238 is not correct, as are most of the advertised MP cam specs. The mis-information started from a single source in the early 1990s and has simple been repeated so many times it is taken as being true.

Also, the advertised duration is measured at 0.008" for that MP cam. Measured at the more conventional 0.006" gives a significantly larger advertised duration. And, FWIW, the duration is 140 @ 0.200"

Lew - these are your measured numbers and I confirmed on my cam.

 

[John Milner]

Yes. It measures 234 @ 0.050". The 238 is not correct, as are most of the advertised MP cam specs. The mis-information started from a single source in the early 1990s and has simple been repeated so many times it is taken as being true.

Thank you, I appreciate the information.

 

[PRHeads]

So, solidly over [email protected], [email protected], [email protected], and a nominal lobe lift of .316”

No wonder they worked reasonably well with single springs.
The ramps are rather mild(not necessarily a bad thing).

The Comp version would have noticeably more area under the curve with its specs being:
[email protected], [email protected], [email protected], with the same lobe lift of .316”.
It is a dual pattern though, with the exhaust lobe specs being:
[email protected], [email protected], [email protected], .316” lift.

I’d expect it to be capable of making more power than the MP version, although it likely wouldn’t rev as high with equal spring loads(especially with todays lifters).

It would be interesting to know how the Mancini version compares to the original.

 

[BSB67]

So, solidly over [email protected], [email protected], [email protected], and a nominal lobe lift of .316”

No wonder they worked reasonably well with single springs.
The ramps are rather mild(not necessarily a bad thing).

The Comp version would have noticeably more area under the curve with its specs being:
[email protected], [email protected], [email protected], with the same lobe lift of .316”.
It is a dual pattern though, with the exhaust lobe specs being:
[email protected], [email protected], [email protected], .316” lift.

I’d expect it to be capable of making more power than the MP version, although it likely wouldn’t rev as high with equal spring loads(especially with todays lifters).

It would be interesting to know how the Mancini version compares to the original.

Talking camshafts is like talking politics. But for all the love and hate for various cam profiles by various cam manufacturers, I'm surprised at how little attention the Comp Magnum cam profiles get, or any profiles other than the Extreme energy series. I will never buy a HFT again, but if I did, the Magnum profiles would be on my short list to look at. I think the 270/276 (5201/5239 lobes) on a 112 would make a great street profile just up from stock, similar to the Crower 271. I think there used to be a 270H Magnum cam (270/270?). Don't know if it's still in the catalog.

 

[lewtot184]

Yes. It measures 234 @ 0.050". The 238 is not correct, as are most of the advertised MP cam specs. The mis-information started from a single source in the early 1990s and has simple been repeated so many times it is taken as being true.

Also, the advertised duration is measured at 0.008" for that MP cam. Measured at the more conventional 0.006" gives a significantly larger advertised duration. And, FWIW, the duration is 140 @ 0.200"

Lew - these are your measured numbers and I confirmed on my cam.

Yep, what I came up with. For some dumb reason mopar rated the .050" number at 85% of advertised number. I doubt a hydraulic tappet cam would last 15 minutes at a true 85%. Ironically the big block engine manual states [email protected] for that cam but a few paragraphs later says the numbers are at 85%. No substitute for putting a degree wheel on them.

 

[furious70]

I ran both 268H and 270H in mild 383's with the same heads and the 270H didn't seem any better which really surprised me because it has "free" lift compared to the 268H. Never did any scientific track testing though.
The 270H worked fine with the OEM 383hp converter.

 

[lewtot184]

Talking camshafts is like talking politics. But for all the love and hate for various cam profiles buy various cam manufacturers, I'm surprised at how little attention the Comp Magnum cam profiles get, or any profiles other than the Extreme energy series. I will never buy a HFT again, but if I did, the Magnum profiles would be on my short list to look at. I think the 270/276 (5201/5239 lobes) on a 112 would make a great street profile just up from stock, similar to the Crower 271. I think there used to be a 270H Magnum cam (270/270?). Don't know if it's still in the catelog.

I've thought about using the 276/.464 for a 272/.455 substitute.

 

[PRHeads]

I often use the Thumper intake lobes for hp street type builds.
Smoother profiles for better upper rpm stability.

But I just feel like you’re really at the mercy of the lifters these days.

That and there’s so many more lobe families to choose from if you step up to a SFT, or HR.