Before spending money on a new cam I'll suggest first buying a copy of the Mopar engine manual to have as a guide.
Check this site for the Mopar Engine Manual, 8th edition, P5249010, it is a give-away price if still available:
http://www.2040-parts.com/mopar-performa...gines-i2187928/

Although the 'usual' cam companies have excellent products, using a cam designed by the same people that designed the engine isn't a bad idea.

With that said, as noted above, the Crower 267HDP is one of my favorite profiles and have used it on many EarlyHemi projects.

Fast 68

I needed to pull the heads as I had a bent valve. Then I checked the lifters an found a couple slightly con caved. It is believed to be the original cam and lifters. I was initially thinking of bumping up a notch but do want to keep the original valve train so that limits my selections. Right now I am leaning toward Crane 3512907 (680101) which is a blueprinted cam. It is in a 1974 true Road Runner with the numbers matching "P' code motor.

Oh

Crane originally made the 3512907 (680101) with the one bolt. According to the latest document they have changed to 3 bolt only. Can you suggest a good 3 bolt timing set?

Dogdays

Good call on the 680101

That's the same one I found here as 3512907 which is now 680101 only three bolt. I didn't know it at the time.

www.scribd.com/doc/24470110/B-RB-ENGINE

I believe this is the same question posted on "For B-Bodies Only"?

PSH, let me know if this info is correct?
Engine is a stock 74 400
Cylinder heads are stock and sent to AeroHead to be rebuilt with the larger 2.14"/1.81" valves, and hardened seats. (No porting or bowl work.)
Car is the '74 Road Runner (likely 3,900+ lbs), stock converter, 3.23:1 rear gear.
I don't think tire size was listed, assuming about a 26-27" tall tire?
Assuming a 235x60x15 tire of 26.1" height, 3.23:1 gear, no converter slipage, then RPM at 60 MPH = 2494.7 RPM, at 80 MPH = 3326.2 RPM, 100 = 4157.8 RPM

The Sealed Power stock 2-bbl replacement cam #KC327 specs are 206/209@ 0.050" duration, 0.434"/0.431" lift, 113 LSA.
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.

Engine numbers:
Bore = 4.340" Stroke = 3.380", Rod Length = 6.358", Block Height = 9.980", Piston compression height should be 1.812", flat top, no valve relief volume.
This puts the piston 0.120" below deck at TDC. Displacement is 400.01 CID.
Assuming a 0.020" head gasket of 5cc volume (4.410" diameter), and an 84cc cylinder head volume, then compression is 7.94:1
Using the FSM advertised duration numbers to calculate dynamic (effective) compression = 6.31:1 This should be about 119 PSI cranking pressure at sea-level? Using the sealed Power KC327 cams 0.050" numbers = 7.40:1 Dynamic compression ratio. I don't have a pressure conversion for 0.050" dynamic numbers?

I recommended the Hughes Engines SEH1620BL-12 cam, 216/220 duration @ 0.050", 0.495"/0.503" lift, 112 LSA.
Hughes shows installing on a 108 centerline, but installed at 107 cl will give the exact same intake closing point @ 0.050" as the KC327 cam installed at the stock 112 cl. This means the dynamic compression calculated at the 0.050" lift numbers would be the same.
In theory (based on effective/dynamic compression, but not accounting for overlap) the larger cam should not give up any low end power to the smaller cam, and then make way more power through the RPM range.
Here are the numbers side-by-side:
CAM KC327 SEH1620BL-12
Intake Duration @ 0.050" 206 216
Exhaust Duration @ 0.050" 209 220
Lobe Seperation angle 113 112
Intake install Center Line 112 107
Intake Opens (BTDC) -9 1
Intake Closes (ABDC) 35 35
Exhaust Opens (BBDC) 38.5 47
Exhaust Closes (ATDC) -9.5 -7
Overlap (0.050 duration) -18.5 -6

Yes same on B-Bodies. looking for all the suggestions i can get. These forums are a wealth on knowledge.

This is my first teardown. It's hard to find the time working full time so it's a slow process working on the bird weekends only.

After getting into the changing the cam idea while she's open I cannot believe all of the endless choices.

Why did you list the 2bbl KC327 and not CS661 4bbl cam?

I do like the SE1620BL but now the .503 and .536 valve lift have me a little concerned. I would prefer to put in a known cam with no issues but that info is hard to find for a particular motor. I have a new single bolt timing set installed. Should I go to thee bolt?

I probably wont research any more till Saturday but I think I have narrowed it down to these albeit conservative cams.
Melling SPD-31, Crane 680101 (supposed to be like stock 74 road runner), Elgin Pro Stock E-1094-P, Hughes SEH16020BL

Much appreciated input.

Getting the valve job done, I wouldn't replace the stock cam with another stock cam.

On specs I like the crower 267HDP... INITIALLY suggested the 271 at FBBO ( although gave the 267 option later ), but is true, it could be a bit big with stock CR, unless you bump out the CR cutting heads and using metallic headgaskets..

Although I WOULD STILL cut the heads ( light 0.020" cut or so ) and use metallic headgasket with any cam you choose.

I used the KC327 because it is likely the specs are very close to what the stock camshaft is, so we have a starting point for comparison.

The CS661 was the stock HP 4-bbl cam, and the engines that used it had over 9:1 compression.

The Hughes cam is going to cost more, and I think you would need to use their valve springs too. But it should also make more power.

If you are trying to keep costs down, the single bolt timing set is likely less expensive than the 3-bolt setup.
The question is what single bolt timing set is it? You do not want the one with the slot for the cam pin. I would at least get one with the 3 crank keyways, usually 0, 4 advance, and 4 retard.
The 9 way adjustable billet units from 440 source are nice, but cost $99. They have a 3 way adjustable for $60. These multi-keyway crank gears are easier to use to degree the cam in than drilling out the cam pin hole and using the offset bushings.

If I get time tonight, I can plug some of the other cam specs into the calculations spreadsheet and see how they look for dynamic compression.

I realize this will probably come off as some Internet guru who just likes to complain, but I'll let the numbers speak for themselves.

One set of numbers is from a clean, used 452 head with the OE valves and OE valve job, the other is from a 452 head than was done at Aerohead like what the op is getting done...... Big valve install, no porting:

Lift--------A/B
.100---61.4/ 67.8
.200--123.6/118.3
.300--184.8/169.5
.400--205.7/198.4
.450--215.0/207.9
.500--222.5/219.9
.550--226.2/224.9
.600--225.1/224.9

The much better option, especially for these milder applications is to retain the std valve sizes and do some mild bowl porting, which not only increases flow but also has much higher discharge coefficient rates(more flow, smaller valve = higher air speed around the valve).

902(1974 head) head with 3 angle seat(stones), back cut OE valve, and very minor bowl blend:

Lift-------flow
.100---67.2
.200--139.0
.300--202.5
.400--230.5
.450--237.0
.500--240.7
.550--243.8
.600--245.7

The big valve install without some accompanying porting is a step backwards for most applications, IMO.
Even if the flow was the same, or slightly higher, the speed of the air around the valve as it leaves the port and enters the cylinder is slower(same amount of air flowing through a bigger hole), which results in more reversion and less efficient cylinder filling.

Fast68, you are on a roll today!

Thank you for a real life example on how installing larger valves can actually reduce flow. I'm sure you have other examples on homemade porting jobs that actually reduced flow.

R.

I do...... But the worst part is....... I have several examples where it wasn't done at "home", but was what someone paid a shop to do......like the example above.

Those Aerohead 452's, after recutting the seats, back cutting the valves, blending the bowls, and opening up the pinch slightly, flowed 261cfm.

Fast68plymouth, do you know what valve springs are used on the AeroHeads?
I called yesterday and Russ was busy, but the lady on the phone said Pioneer G911? I looked and pioneer does not have a G911, but maybe it is the Pioneer S-1050? That is a 1.525"OD spring, lists 117-132@1.875", 341-369@1.375"
That would be similar to a comp 911 spring, but with a higher spring rate?
Or maybe they just use the Comp 911 spring and they told me the wrong vendor?

The G911 is an Indy number afaik, and I have seen at least 4 different springs from them where the invoice listed them as "G911".

What I've been getting recently, listed as the G911, is about 150@1.900/350@1.300/CB@1.200.

Prior to that they were very similar to what would come on RPM heads, and I had a few sets of heads years ago where they were even softer than the RPM style.... Two different versions of those.
They were too soft to use on anything(IMO), so I ended up adding an inner to make them useable.

I just got some heads two days ago with the "G911" springs..... I'll have to see where they stack up.
It's always a mystery.

Lunati 10210241LK cam (single bolt timing set) that is 216/228@ 0.050", 0.454"/0.480" lift, 112 LSA , $208 price for cam and lifter kit looks good for the price.

The Summit K6400 214/222@0.050", 0.444"/0.466", 112 lsa specs look OK too (the advertised duration looks pretty big, but might be rated at 0.002"?) and is really inexpensive $118 cam/lifter kit. I never used one of these so I don't know about their quality?

I also noticed the Howards CL720031-12 cam 215/223@ 0.050", 0.446"/0.465, 112 LSA $220, or $249 for the "Max Certified" version MC720031-12
I had to look at their web page to find out what the "Max Certified" was, it looks like it includes a bottle of break-in oil additive and a 5-year insurance policy on the cam/lifters (if you add their oil additive at each oil change.)

the oil additive is about $8, so what do you think about paying an extra $21 for a 5-year warranty?

I have a small Summit cam in my 440 pickup and the bigger Summit cam in my 440 Valiant. Quality is excellent. I have been running both cams for 2 years now without a problem. The 440 in my pickup is a late model low compression engine and the small cam idles smooth and creates lot's of torque. The 440 in my Valiant has 9.25 compression and the larger cam pulls hard. I can't say anything bad about them and would gladly use them again.

The small Summit cam would certainly be on my short list for the OP's combo.

fast 68

Those summit cams are very economical.

Does anyone know the max valve lift for this engine. Don't want to play with clay.

Lift has nothing to do with clearance.

It's duration that uses up clearance(amount of lift at TDC).

On a stock 400 that has the pistons down the hole .080+, and heads that havent been cut a bunch, pretty much any cam with less than mid-230's @.050 should fit okay.
So, anything that's "appropriate" for the rest of the combo shouldn't be a problem.

The only place where lift might be a concern with that build and stock heads is retainer to seal clearance.

Thank you