I'm looking for a cam for my stock '68 383.
I am adding a 4 bbl and dual exhaust with H.P. manifolds.
otherwise it's stock.
Going back into my New port.
I have zero experience with cams.

I was wondering just what the stock specs would be.

I'm looking at a Hughes unit.
They suggested one with a rough idle and poor vacuum, along with rear gar change..
I was not wanting that, power brakes and a heavy car.
What I want is more torque.
Here's what I am looking at.
SEH1016BL-12
lift intake 0.320
exhaust 0.330
duration
intake 210*
exhaust 216*
Is this preferable to the stock unit?

check a thread about 383HP 330vs335HP which has being discused latelly and will find the info about the stock specs between the 3 383 setups available by those years

Thank-You.
I'll look for it.

I'm surprised Hughes recommended one with a rough idle/low vacuum & a gear change for your mild DD. I'd consider one of the Summit house grinds (there's 2, a mild & one very slightly hotter both of which have gotten good reviews. I have one uninstalled as of now. they are inexpensive.

There's nothing wrong with a stock replacement magnum cam. From MP or Crane or other. For your application it will be nice and quite and give good throttle response. That Hughes cam you spec'd would work good to. Though its got faster ramps than the stock cam so it could have a little more valve train noise.

The Hughes 1016 has the same duration at 50 as the stock HP cam, but lift is 0.480 rather than 0.455 or whatever, and LSA is slightly tighter at 212 rather than 115 or so. Those two changes make it a better cam,

Both Crane and Comp have versions of the stock HP cam which have been tweaked by their lobe designers to have smoother valve action. If you are a Crower fan the 267HDP is a very nice 383 cam.

It's hard to recommend a MP cam because they appear to be trying to keep FCA out of bankruptcy by asking unbelievable money for cams.

Summit cams? The small one is too small and the large one is too big, with more than 230 degrees at 50 on the intake lobe.

R.

WHO SAY ME? LOL

I think the Hughes seems you are looking at is a good option too ( in my theorical "knowledgement" ).

Usually MP ( per what I have read ) never makes public the correct duration at 0.050 lift but a 85% estimation of the total duration... is like that on stock cams, or stock cams 0.050" duration is more exact ?

The MP correction factors for @.050 duration, as i recall, are 85% for aftermarket performance cams and 77.7% for stock cams.

Using the 77.7 factor for stock magnum cam gives:
268*.777 = 208
284*.777 = 220

This site seems to verify these numbers:
http://victorylibrary.com/mopar/mpcam-tech-c.htm

BUT... Then you have the measurements that BradH did some years ago from an actual A12 six pack cam (which should have the same specs as magnum cam). Here is a quote from Brad:

"My measurements of an OEM '69 1/2 440 6BBL cam:
292 @ .004" / 214 @ .050" / 124 @ .200" / .449" (1.5)
310 @ .004" / 226 @ .050" / 133 @ .200" / .459" (1.5)
LSA 115 (measured 112 ICL installed "straight up", so it had 3* advance ground in)

It's virtually identical to the Speed Pro CS661, which specs out as adv. duration 292 intake/ 309 exhaust, duration @ .050 of 214 intake and 225 exhaust, valve lift of .449 intake and .464 exhaust, lobe C/L is 115. Erson also listed one that's virtually the same w/ the exception of a 1-degree tighter LSA, IIRC. "

Based on that info, I take it this was originally a 2bbl motor.
If that's the case, than a valve spring upgrade will be required for virtually any cam swap.

Personally, for that application I feel the smaller summit cam would work just fine, along with a set of stock replacement hp springs.
Swap out the valve seals while you're in there.

The 1969 1/2 M code six pack 440 motors where the only stock production 440 motors that came with the three bolt cams and the low taper lifters like the 426 Street Hemi motors came with
Your right on the cam specs. on the 375 HP and 390 HP six pack motors being the same
Ma Mopar has done some things on special package vehicles that make me really wonder why

This came up last month:

https://board.moparts.org/ubbthreads/ubbt...tml#Post2321416

For reference, Sealed power lists two stock replacement cams:
The Sealed Power stock 2-bbl replacement cam #KC327 specs are 206/209@ 0.050" duration, 0.434"/0.431" lift, 113 LSA.

The Sealed Power stock 4-bbl replacement cam #KC661 specs are 214/225@ 0.050" duration, 0.449"/0.464" lift, 115 LSA.

The specs seem to be in-line, but not exactly, what the factory advertised.

From the '71 Factory Service Manual, the 2-bbl cams is 260/268 advertised duration, 0.425"/0.435" lift, 113 LSA, Intake open 18 BTDC, Intake Close 62 ABDC, Exhaust Open 68 BBDC, Exhaust Close 20 ATDC, 38 degrees overlap.
To get those valve events, the cam would need to be installed 112 centerline.

The FSM for the 4bb cam is 268/284 advertised duration, 0.450"/0.458" lift, 115 LSA, Intake open 21 BTDC, Intake Close 67 ABDC, Exhaust Open 79 BBDC, Exhaust Close 25 ATDC, 46 degrees overlap.
To get those valve events, the cam would need to be installed 113 centerline.

The Hughes SEH1016BL is a nice cam for what you are doing.
Specs 210/216@ 0.050", valve lift 0.480"/0.495", 112 LSA, install intake centerline 108 degrees.

On paper the hughes cam looks to be "between" the two cams, but this does not take into account the rate-of-lift of the lobe profile.

Most likely, the Hughes cam at 0.200" duration is as large as the factory 4-bbl cam, while having seat-to-seat valve timing close to the factory 2-bbl cam. These are good things, it should idle nice and make more power/torque through the entire power curve.

Not sure what your compression ratio is 9:1+?, but if you had about a 2200-2500 stall converter, and maybe 3.23:1 gears I would suggest the Hughes SEH1620BL cam.

I would not use the Whiplash (SMC2942BL) cam in you application.

You will need to upgrade the stock valve springs. If they are stock, they likely need replaced (because of age/loss of pressure) no matter what cam you use.

The main issue with trying to use any Mopar published info on running duration for the factory cams(or the MP cams for that matter), is they don't say at what tappet lift those numbers are for.

If using any of the "normal" industry standard checking points/lifts, the 268/284 figures for the factory hp cam aren't even close.

As is illustrated above, when using the SAE method/checking lift(.006/rocker ratio), an actual factory HP cam measured at 292/310 duration.

The last "292" MP 509 cam I checked was 305.5@.006....... So who knows what checking height they are using to arrive at 292.

Camshaft duration numbers without knowing the checking heights are about as useful as head airflow numbers without test pressures. It's just a number......that can't really be used as a basis for comparison.