sbc 400 what heads? - Chevelle Tech
2001 General Tech questions from 2001

 
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post #1 of 12 (permalink) Old Dec 26th, 01, 8:24 AM Thread Starter
 
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Location: caldwell, idaho
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i want to build a slamm block 400, i was wondering if there were any good geads for this motor that dont cost a wad of cash. they will have to be iron, only when hell freezes over will i be able to afford aluminum heads. thanks for the help
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post #2 of 12 (permalink) Old Dec 26th, 01, 9:44 AM
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need some more info than the block. Like for instance whats the compression going to be? What cam are you using? What are you going to be using the car for?

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"When life hands you lemons, ask for a bottle of tequila and salt."
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post #3 of 12 (permalink) Old Dec 26th, 01, 2:51 PM Thread Starter
 
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9-9.5:1 compression. 226/234 dur at .050 480/501 lift, 200r4 3.55 gear. these arent exact #s but some where in this area. the car will mostly be a street car/ daily driver very minimal track duty

[This message has been edited by badcam (edited 12-26-2001).]
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post #4 of 12 (permalink) Old Dec 26th, 01, 7:03 PM
 
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I have a sbc 400 in my 70 velle and I bought a pair of aluminum trick flow heads 64cc.. I paid about $800 bucks for them and about $100 bucks for a set of roller rockers.. I'm here to tell you it rocks!!!
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post #5 of 12 (permalink) Old Dec 26th, 01, 8:38 PM
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406 under construction, Dart Sportsman II 215cc runner 64cc chamber, double springs large O.D. solid roller setup
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post #6 of 12 (permalink) Old Dec 27th, 01, 6:30 AM
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If you want to get started with the LEAST AMOUNT OF EXPENSE FOR HEADS, use 70-74 stock 400 heads. The 400 ports are as big as any SB heads and they come with 1.94-1.5 valves. The first upgrade you can do is to open them to 2.02 or 2.05 intake valves and 1.6 exhaust valves. If you have a VERY GOOD head person in your area who will not charge an arm and a leg, you could have them port matched and have some light bowl blending done. The STOCK 70-74 heads, which are 76cc heads, used with 5.7 (350) rods and flat top pistons, will produce about 9.6 comp.

DO NOT USE ANY STOCK 75-LATER CHEVY HEADS ON A 400. In 1975, Chevy started cutting corners on their heads to save a little weight. In 75 the heads had a second exhaust crossover port added which produced more head heat. And by the late 70s, all SB heads (except the Bowtie heads) were light weight, thin wall castings. ANY machinist who has lots of experience with SB heads will tell you that Mid-70s and later heads are either cracked when they come in, or, they probably will crack soon.

For performance, endurance and longevity, your VERY BEST investment in a head will be one of the iron, BIG PORT aftermarket heads, such as World or Dart with 225cc or larger intake ports will be the most ideal head to use. A 235-245cc port will provide the best performance. I don't think there are ANY alum heads with ports this big right out of the box. Also, heads with the 2.08 valves will be the best to use.
I have pointed this out here many times before. Performance wise, a BB 396-402 will blow the doors off of a SB400, even though they are the same displacement. The reason is because BB heads can BREATHE! PERIOD! The BB heads with the the smallest valves and ports (such as a bone stock oval port BB head) ARE STILL BIGGER THAN SB HEADS WITH THE BIGGEST PORTS AND VALVES. You physically CANNOT install a valve in a SB head that is as big as a small BB valve. So, the bottom line is, there is no such thing as a head with ports/valves too big for a SB400. When you have 400+ cubic inches, it needs to be able to breathe, so don't be concerned about using big port/valve heads.

And last, keep in mind, as displacement increases, the engine can handle a cam with a larger profile. For a SB400, a lift of .500 is no problem. But, then this brings up another issue. Most SB heads come with pressed in rocker studs. For a cam with .450 or more lift, it is almost mandatory to have screw in studs installed. The reason is because BOTH the bigger lift AND the amount of spring pressure required to handle this much lift will possibly cause the pressed in studs to pull out. ALMOST ALL aftermarket heads come with screw in studs.



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Tom Parsons

[This message has been edited by DZAUTO (edited 12-27-2001).]
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post #7 of 12 (permalink) Old Dec 27th, 01, 9:27 AM Thread Starter
 
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thanks for the info DZAUTO, but the only reason i'm building a small block instead of a big block is because i can't afford to put gas in one and i can't even afford to buy one to build, anyone in end of the earth idaho can feel my pain on that issue.
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post #8 of 12 (permalink) Old Dec 27th, 01, 3:50 PM
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For just a STRAIGHT rebuild of a SB400, the cost will be just a LITTLE higher than to rebuild a 350. The machine work, straight across the board, will be the same price. Vatting a block is the same. Boring a block is the same. Turning the crank is the same, etc, etc. ALL, I mean ALL the parts, except the pistons and gaskets,will be the same price as for a 350. Building a 400 (406 with .030 bore) with 5.7 (350) rods is now so common, that the price for pistons is now just a tiny bit more than 350 pistons. The ONLY difference in gaskets is the head gaskets in a gasket set, which, again are just a tiny bit more than a 350 gasket set. If you are really, really, really on a tight budget, use the original 400 heads, have a good valve job done and keep cam lift around .450 max. You REALLY should build the 400 with the longer 350 rods. You should be able to find a good set of used 350 rods for next to nothing. If you just rebuilt the 400 with 350 rods, have a good valve job done on the stock heads, shop around the mail order houses for the best price for parts (Summit is always hard to beat), have the engine balanced and do the assembly yourself, you will come out pretty cheap and in the end, you will have a motor that will last and provide gobs of torque.
As time goes by, and your funds improve, you can do some upgrades (heads, intake carb, headers, etc).

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Tom Parsons
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post #9 of 12 (permalink) Old May 8th, 06, 10:09 AM
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Rob
 
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Re: sbc 400 what heads?

For a 400 that seems like a small cam. Granted mine is a hyd roller but has .530 lift. I would think that you could get better heads to let her breathe. A 200 cc runner would be great. What about Brodix Iron Killers what are they like price wise?

I run a dished piston because I have a 64cc chamber. Still puts me in around 9.7:1 or so. I also used a 5.7 rod but I also got a small base circle cam to clear those rods and rod bolts.

1966 Chevelle Malibu 489, 870 Holley, Edelbrock RPM Air Gap, aluminum heads Patriot 315, TH 400 Gearvendors OD/UD, 12" disks up front and 9 inch with 3.50s.

1966 Chevelle wagon, 408 SB, 3.73 12 bolt, 700R4, 12" discs front 10" rear.

1968 GMC 3 door Suburban C10 454 4L80E EFI

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post #10 of 12 (permalink) Old Feb 17th, 07, 8:56 PM
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Frank Riley
 
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Re: sbc 400 what heads?

1

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post #11 of 12 (permalink) Old Feb 17th, 07, 8:59 PM
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Frank Riley
 
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Re: sbc 400 what heads?

Hard to beat a set of SBC Edelbrock RPM heads for the money at about a grand, you''ll have almost $500 in a set of iron heads done right anyway. And with the Aluminum heads you won't have to worry about detonation with comp ratios up to at least 10-1 on 87 octane.

PS, Just don't forget the steam holes for the 400, they'll need to be added either way you go.

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post #12 of 12 (permalink) Old Feb 17th, 07, 9:35 PM
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Eric
 
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Re: sbc 400 what heads?

BadCam,I hear you.I built a 412 about 15 years ago.Very straight forward and a blast to drive.
Stock crank
Stock rods with ARP bolts.
Flat top pistons(I think my only mistake),should have used a small dish.
Balanced and Blueprinted.
Perfect Circle Cam with .480 lift and 230*@.050
Factory 400 heads,gasket matched,3 angle valve job,and pocket ported with 1.94 and 1.60 Manley Budget valves.
Performer Intake
600 Vac.Sec.Holley.
1 1/2 primary tube headers with 2 1/4 exhaust,and Turbo mufflers.
Stock HEI ignition with recurve kit.
1800-2200 B&M Converter
400 Turbo with shift kit.
10 Bolt rear with 3.42 gears.

This combo was in my 86 Silverado.It was a blast to drive.Every time the thing shifted,it would bark the tires.And I used 275/60 R15"s on a 8.5 in wheel.The truck also weighed over 4000 lbs.,and got about 14 MPG.
I swear it would run faster uphill than it would downhill.
Lord,I miss that truck.

Just a street car.
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