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I am in the process of building a SB400 with 10:1 CR, Holley 650 dp, Edelbrock RPM and am stuck between a choice of cams. I have narrowed my search down to 3 grinds. One cam, Lunati #00012, gives me alot of torque, 453 at 2000 rpm, then gradually tapers off. But, it maxs out at only 321 hp at around 4000. Another cam, Comp Mag 292H starts out at around 334 lbs torque at 2000 rpm and rises to 434 lbs torque at 4500 rpm. This cam maxs out at 415 hp at 5500 rpm. This seems like the logical choice, but, I know torque gets things moving in a hurry, such as a heavy chevelle. Any suggestions on which way to go or even another cam choice. Also, should I stay with my Edelbrock RPM or go single-plane? This car is a street/strip car. Thanks in advance to all!
 

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Dude, did you go with 5.7 or 6 inch rods?
EVERYTHING I've read about torque suggests 6" as the rod of choice.

Also, if geared for it, and with 400 cubes, you shouldn't miss the low end, and it oughta ROCK at higher R's!!!

I'll be watching this thread, as a 383 or 400 is in my future!

Dave H.
81ElCamino (wimpy 360 cid currently)
 

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RB,
First of all, I presume since you say you are building the 400, that means it has or is going to a machine shop and will be bored to clean up the cylinders. Maybe .030 over? That means a 406ci SB. Torque is directly related to displacement. So with this displacement, you can afford to sacrifice a little low end. Generally speaking, a well built SB406 will, or can, provide you with similar performance to at least that of a base 396. And we all know that a stock, hydraulic 396 is very strong compared to any SB, plus the weight savings. I am sure that you will discover that you will be very happy by building for a little more top end and that what you loose on the low end will not be a significant loss. 81 is right, at least go with a 5.7 rod, 6 is better. I recently built a SB400 for my wife's 70 conv with full pwr and air. I used 5.7 rods, an early original Z28 intake with an adaptor for a Q-jet, a cam with .480 lift and about 230 @ .050, a wide Muncie, 3.07 12bolt posi and it has excellent all around performance. For drag racing, it would not be good off the line, but this is a street car for my wife. And in town, it has PLENTY of low end. On the interstate, with the cruise set, it is great because the rpm is low. My point is, with your engine built for more top end, you will have plenty of low end with a 406SB to do the job. And yes, if you really want to be killer, it's going to require a bigger BB.

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Opinions are like...Oh, never mind.


With all due respect to DZAUTO, here's my opinion. If the car is mostly a driver, I would want the largest, flattest torque curve I could get. Reason: that's what you feel in your everyday driving. How often will you get to use those additional "peak" horsepower?

As an exaggerated analogy, I used to drive alot of sports cars. What I hated about them was that you had to thrash them all the time to feel any power, like a V8. A Lotus Esprit Turbo feels like a Pinto at low speeds. When you get the turbo spooled up, Katy bar the door! That thing would fly.

If, on the other hand, your car's purpose is primarily strip, go for peak horsepower.
 

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The 292 cam sounds good . Peak HP at 5500 should give you a nice run to just under 6000. In my experience a single plane wakes up at close to 5000 on up. They can be louggie at 2000-4000. DZ mentioned the Z28 mani. Excellent choice. It's a high rise dual. The Edel Performer RPM should be OK to.

I'm currently running a 396 that pulls to 6000 and I'll tell you that the 750 DP is not too much carb. You might be clightly under carbed for the 400. But give the 650 a whirl.

Good luck on your build up.

[This message has been edited by Gene Chas (edited 07-13-99).]
 

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Rbomar I've got a 406 with 11.00 to 1 flat tops with 2 valve reliefs. I also have sportsman 2 heads with 64cc heads with 2.02 and 1.60 valves. Comp cams extreme energy 274
.490 .487 230, 236 at .050 cam. Performer rpm
q-jet intake. With a Carburetor Shop built q-jet, Hooker Comp. Headers 1 5/8 with ceramacoat.Crane roller rocker arms with 1.5 ratio the silver ones. 480ftlbs of torque at 3500rpms 375hp at 5,000rpms on the dyno. I will be running at the track in the next 2 weeks. I think I got all the bugs out finally after getting in the chevelle. Hoping 12.70's about a 105mph with slicks. 3.36 gears and 2400rpm B&M converter. I also used the 5.65 rods and had them balanced.

[This message has been edited by plain 69 (edited 07-13-99).]

[This message has been edited by plain 69 (edited 07-13-99).]
 

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The 292 and a good double plane intake sounds logical for a street/strip. I would stay away from the single plane. From what i have been told the smaller rods build more torque but the longer increase life, piston quench, and horsepower. so if u dont have the rotating assembly done i would suggest the 6.0's. They will also give you a higher rod/stroke % which will allow your engine to rev faster. Hope this helps

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Here's another cam choice for you: Lunati grind #30112 H225-235 It has the following profile: 225/235 duration, .477 - .507 lift, 110 centerline.

This cam is WELL suited for heavier cars like our Chevelles. Give Lunati a call (901) 365-0950. Good luck!

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70' Malibu - 383 'Dental Gas' Inhaling Stroker! Gold Member #39
Chevellz Alwayz!
 
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