First off, you don`t need a dual pattern cam. If the exhaust is using headers and a low restriction system having more lift and duration on the intake side does zero good power wise. 400`s swallow up cams pretty good so your safe up to around the .240 range @.050 in duration.
I would use this cam from Isky in a retro roller. 201520.
It`s a retro roller design with .240 intake and exhaust duration @.050 and specs out how you want it.
I would use a Dual plane intake and a 800cfm carb.

 

Thanks for the opinions, guys. Is the dual pattern simply not needed for my build, or is it detrimental to my build?

I've read that the 400 sbc prefers a single pattern cam, but never understood why. I asked this question of a tech at Howard's Cams, prior to creating this thread, and he basically said "hogwash- a single pattern would provide no advantage in my build, although he certainly grind a custom stick for my application, if I wanted."

By the way, do you really consider a 2600 stall "a near stock" stall speed?

 

Stall speeds act at different speeds depending on engine, torque, weight, gear ratio, the whole nine yards.
Why I perfer a single pattern cam? In stock form, the chevy exhaust port is very good. It`s open, has a gradual curve and flows nicely.
The intake port? Not so good. Now flip that over to ford ports. Nice open intake ports. Exhaust ports are absolutely horrible, small, kinked, and need major surgury to flow better. Hey, I`m not one to argue with a cam company, but if you look on Isky`s website, the agree with what I`m saying.
But that`s not where I got it from, I got it from I`ll admit Smokey Yunick and it seemed to make sense to me as the factory did the same thing.
375 horse 327 in 1964, solid lifter single pattern cam.
350 horse 327 L79 hydraulic lifter, single pattern cam.
370 horse 350 LT-1 Solid lifter single pattern cam.
The factory knew these engines would more than likely be swapped over to headers.
Now take the 350 and 327`s that were intermediate, 300 horse range. They had a dual pattern cam, and the vehicles they came in had single exhausts so it was done since the exhaust side didn`t breathe as well as it could have. Not my ride, you may run what you wish.

 

Yes a "2600 stall" is considered near stock. its essentually a stock GM converter with the fins bent a bit more.

If you bend the arm of a cam help tech, on the phone he will sell you a dual pattern cam ( or what ever else you think you need) if you think thats what you got to have. I would do the same thing, before you hang up the phone. There are there to sell you a cam.

You, many people shoot them selves in the foot when calling up about a cam recomendation and then start going on about this or that, essentually telling the doctor how to cure.


I recomended the specific custom cam I did so it suites the overall purpose with what you got and what you are trying to achieve.

The single pattern makes more mid range torque overall.

Give Comp a call on this one . They will grind it for you.

Degree it in and enjoy. It is "just right".

I understand what you're saying- but that's not the way it happened. I gave him no indication as to what cam I was looking at, other than a retro hydraulic roller. He suggested that specific dual pattern cam (and of course they sell single patterns, and custom grinds.) I'm not trying to be argumentative, but I've received so many differing opinions that my head is starting to spin.

Thanks to both of you for the suggestions.

 

*update*

My engine builder, and a tech from AFR (Jeremy), recommend a more radical cam- around 248/254 at .50 lift. Iv'e done tons of research on this and it seems very few are running a cam this "hot" on a 406 or 408, and this concerns me a little.

I don't want to be undercammed (go big or go home, I always say), but I also don't want a cam that runs like crap on the street. Both my builder and the AFR tech said a 408 *needs* a cam like this for big power, and it will be fine on the street.

Here are the cams I'm now looking at:

Comp cam XR300HR- 248/254 @.50, 300/306 advertised, .562/.58 lift w/ 1.5s, 110 LSA.

Howards cam 113155-10, 247/255 @.50, 300/308 advertised. .6/.6 lift w/ 1.5s, 110 LSA.

I'm leaning towards the Howards, as I like the idea of being able to take advantage of the AFR's high flow with the increased lift. I ordered the AFR 8019 springs, good to .65 lift (I can still change back to stock springs as the heads won't ship for 2 weeks). According to my calculations, the Howards cam lift w/ 1.6 roller rockers will be .64.

Is such a high lift a concern? Why is no one else running such a high lift? I do plan to order the upgraded Howards lifters that can handle the spring pressure.

Is the extra lift worth the increased cost (upgraded lifters and springs will run me about $300 more than lifters and spring for under .6 lift.)

Again, any input is appreciated.

 

You have an engine builder that you supposedly trust and you have conferred with Comp Cams. What is the problem that you don't want to go with their recommendation?

 

If you want this cam: Get a new converter and gears. FIRST. This cam will not work with what you got.

It will not idle in gear with the 2600 stall. Needs a 10" 3500 stall and 3.73-4.10 gears.

Like I said , when you get the gears and converter you can step up the cam.

2600 stall and 3.07 gears you are not going to like it.

Some people have to learn the hard way.

Call Comp Cams. Show them the cam lobes I recomended for the 2600 stall and 3.07 gears. They will advise.

I don't have the converter yet- the 2600 was my estimation, based on the cam I was originally looking at. I can certainly order I higher stall and I do plan to go to 3.73s.

I did call comp cams- they recommended camshaft Part # 12-433-8 Grind # XR288HR-10 Duration @ 0.006": 288° / 294° Duration @ 0.050": 236° / 242° Max Lift w/ 1.5RR: .520" / .540" Lobe Separation: 110°. They were aware of the gears as well. I told them I have not chosen a converter yet.

Any thoughts on my "high lift" concerns?

 

You have an engine builder that you supposedly trust and you have conferred with Comp Cams. What is the problem that you don't want to go with their recommendation?

My engine builder, AFR, Comp cams, and Howards Cams have widely varying opinions as to what would work best. Hence, my dilema.

 

*update*

My engine builder, and a tech from AFR (Jeremy), recommend a more radical cam- around 248/254 at .50 lift. Iv'e done tons of research on this and it seems very few are running a cam this "hot" on a 406 or 408, and this concerns me a little.

Trust me, lots of people run hotter cams than that with 400+ cube motors. Bigger motors can run bigger cams and not have the driveability problems and idling problems that smaller motors do.

I don't want to be undercammed (go big or go home, I always say), but I also don't want a cam that runs like crap on the street. Both my builder and the AFR tech said a 408 *needs* a cam like this for big power, and it will be fine on the street.

Side note: you WILL NOT need a smaller base circle cam.

The higher the stall speed of the converter the easier it will be for a radical camshaft to be tolerable on the street. If you run a "tight" low rpm converter, and big cam, it may surge and buck at low rpm, because the transmission will be lugging the motor down low. I run a 5200rpm converter on the street, and the motor has zero issues.

*Here are the cams I'm now looking at:

Comp cam XR300HR- 248/254 @.50, 300/306 advertised, .562/.58 lift w/ 1.5s, 110 LSA.

Howards cam 113155-10, 247/255 @.50, 300/308 advertised. .6/.6 lift w/ 1.5s, 110 LSA.

I'm leaning towards the Howards, as I like the idea of being able to take advantage of the AFR's high flow with the increased lift. I ordered the AFR 8019 springs, good to .65 lift (I can still change back to stock springs as the heads won't ship for 2 weeks). According to my calculations, the Howards cam lift w/ 1.6 roller rockers will be .64.

Is such a high lift a concern? Why is no one else running such a high lift? I do plan to order the upgraded Howards lifters that can handle the spring pressure.

Is the extra lift worth the increased cost (upgraded lifters and springs will run me about $300 more than lifters and spring for under .6 lift.)

Again, any input is appreciated.

Usually cams are split duration favoring the exhaust side. Most cylinder heads have very poor exhaust flow compared to the intake side. That is why most cams are ground that way. AFR heads are exceptional on the exhaust side in relation to their intake flow.

Make sure those AFR springs (8019) have the same install height as the springs you have right now. Just because a spring says it can handle .650" of lift, doesn't mean it will work. If the spring has an install height of 1.950" and you put them on your heads and they install at 1.850", they will coil bind at max lift.