Thread: Tell me about a 400 sb

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OK, the '82's were a little lighter than their predecessors, curb weight at right around 2900 lbs. Add a 200 lb driver and you're at 3100 lbs. Assuming this is a '96-'02 Vortec motor, the static compression ratio will be 9.4:1, with the best iron production heads that Chevrolet ever mass-produced for a Gen I motor.

Cam will be a factory hydraulic roller that is limited to around a 0.530" valve lift, using a standard 1.5 rocker. More lift than that can cause the roller to disconnect from the dogbone and things get ugly in a hurry. You can use a 1.6 rocker to get more lift, but it is not worth it in my opinion, because of the extra effort that it introduces into the valvetrain. Those components have an extraordinary job to do in the first place, without adding undue stress for a 10-12 horsepower gain. I don't use or recommend extreme energy grind cams for the same reason. If you are not seeking every last horsepower to drive around a competitor in a racing venue, then use a cam that is a little easier on the valvetrain and get some extra mileage from the package. Other thing about the L31 Vortec heads is that they stop gaining flow at about 0.500" valve lift, so there is no reason to go with more. When you reach max flow at a certain lift, then you make more horsepower by extending duration a little, limited by the static compression ratio of the motor.

OK, if you are with me so far, let's move on to the intake manifold. The absolute best intake manifold you could choose for a street motor is a high-rise, dual-plane design (NTFDAY might argue with me about that and he has valid reasons). When Chevrolet designed the Z-28 5-liter motor for introduction into the 1967 model year Camaro, they contracted with the Winters Foundry to cast the all-aluminum intake manifolds for the motor. It was a tall dual-plane design that proved so popular (read effective) that Edelbrock, Holley and Weiand copied and began production on their own part numbers for the aftermarket.

The Edelbrock 7116 or Weiand 8151 would be my choices.
https://www.summitracing.com/parts/edl-7116
https://autoplicity.com/3549338-holl...iand-manifolds

I would avoid using an air gap intake manifold for use on the street. If you want to use them in drag or other kinds of racing, that's OK, but avoid them for street use due to possible drivability problems in coolish weather. The intake manifold needs to stay really good and hot to help atomize the mixture for complete combustion in a street driving venue. Use the Air-Gap if you need another 10 horsepower in a racing venue and are not concerned about drivability.

For an everyday driver, a 600 is all the carburetor you will need. For max horsepower on a 350 with headers and gears, use a 750.

You will want to pay attention to the squish/quench and keep it between 0.035" and 0.045" by juggling head gasket thickness. A thin squish will insure that the motor can operate on pump gas without detonating. If you want to PM me about this, feel free.

For a cam, I'd use a mild grind due to using cast iron manifolds. Headers begin to shine at higher rpm's, so since you will be using logs, I'd use a cam that makes driving pleasurable in the lower ranges, with great throttle response and low end torque.
Here is a suggestion for you, a step-nose cam and lifters from Howards......
CL180315-10 kit, cam and lifters.....
Advertised duration 262/268
0.050" duration 209/215
Valve lift 0.465"/0.470"
Intake lobe centerline 106
Exhaust lobe centerline 114
Lobe separation angle 110
Hydraulic Intensity 53
Power range 1000-4400 rpm's (will work great with a stock 3-speed auto or an overdrive transmission, together with stock converter and gears, although a rear gear in the mid 3's would work really well.) If you think you will need a little less power down low and would rather have increased manifold vacuum for power brakes, have Howards grind the cam on a 112 degree lobe center rather than a 110. 108/116/112.

Call Howards and discuss this cam with them, tell them everything about your driving habits and what you expect from the motor.
http://howardscams.com/
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Originally Posted by techinspector1

OK, if you are with me so far, let's move on to the intake manifold. The absolute best intake manifold you could choose for a street motor is a high-rise, dual-plane design (NTFDAY might argue with me about that and he has valid reasons). When Chevrolet designed the Z-28 5-liter motor for introduction into the 1967 model year Camaro, they contracted with the Winters Foundry to cast the all-aluminum intake manifolds for the motor. It was a tall dual-plane design that proved so popular (read effective) that Edelbrock, Holley and Weiand copied and began production on their own part numbers for the aftermarket.

He's right about that. I prefer an Offy 360º which is s a single plane medium rise manifold with a split plenum. You basically get the best of both worlds for the street. It more or less is a matter of choice or opinion and I have experience with an Offy. Someday if I get ambitious I have a dual 4 Offy 360º setting in the garage that I want to put on the Vette, mainly for looks as IMHO nothing looks better than dual quads unless they're sitting on a blower.