well i was almost going to start my 406 project.. and i always assumed that SLP made headers for these engines, but after i called them, they said they dont. does anyome else make headers for chevy 400's? also im trying to maek this engine street legal, so it needs those holes/pipes going into the headers for all the smog stuff.

 

try hedman I think hey make it with the o2 sensor and pipes.

 

Anything that fits any other SBC should fit a 400.

 

SLP 1 3/4" headers will fit your 406 small block engine. I dunno why they said they wouldnt, but small block heads are all the same.

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.23 @ 107.62 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

Just because it fit don't mean its right. 1-5/8" primaries would give up lots of HP over 1-3/4" primaries with shortie headers. On long tube headers 1-5/8" might be ok, but i don't have the experiance to say for sure.

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-Tas
'89 Formula WS-6

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

To be installed eventually far far far into the future: Yours if the price is right and I don't have to ship :
Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248), Catco 3" cat, and injector spacer.

Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options
AOL IM: superGRtaz

 

All SBC V8 engines use the same bolt pattern exhaust manifolds. Bigger engines need bigger exhaust but it also depends on the heads you plan to use. Stock unported heads will benifit more with 1 5/8" primary tube headers but don't overlook the SLP 1 3/4" headers if you plan on really doing some performance work.

I'm sure there are many cars out there with 1 3/4" SLP's that would notice a performance difference by going to a 1 5/8" header. Bigger is not always better. The benifits of larger tube headers are really only noticed about 5500 rpm and driving on the street rairly gets over that.


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Follow my racing progress on Stephen's racing page
and check out the race car

87 IROC-Z SuperPro ET Bracket Race Car
461 naturally aspirated Big Block

Best ET on a time slip: 11.242 altitude corrected to 10.89
Best MPH on a time slip: 121.52 altitude corrected to 125.89
Altitude corrected rear wheel HP: 497.9
Best 60 foot: 1.546

Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley

 

I'd like to see someone with similar mods as me but with Edelbrock headers dyno their car, and we'll see who gives up horsepower and torque. I'm trying to get Tom Keliher to dyno but it hasnt happened yet.

 

just remember, too small is always better then too big

any header for a SBC will fit the 400. try getting some hooker long tubes and see if they fit.

 

Uhm... why is too small better than too big?

 

i snagged a 400 for my bird. i think i am going to go with the 1 5/8 long tubes, one the cost, i just cant get down on the 360 dollar tag for the super comps. IMO 1 5/8 long tubes wont give up that much if any power to 1 3/4 long tubes. shorties may be a different story just because of the design. my buddy has a 71 bird with a built 455 and we are running 1 3/4, he thought about running 1 7/8 or 2 inch. but because of the cost, and the fact that 90 percent of the cars running 11's and 12's that have 455's in every ponitac magazine i have ever read are running 1 3/4, we decided to go with that. my theroy is that on a mild SBC, yes even a 400 1 5/8 arent gonna hurt ya. thats just my .02

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Wide Open Till You See God...Then Brake

 

too small is better then too big, i got that quote from the guy who run the School Of Automotive Machinests out of the latest GMHTP. If you go too small at least you still have high flow velocity and good scavanging. if you go too big, then you get a slow lazy flow that doesnt scavange worth a damn. so thats the simple explaination as to why smaller is better.

 

see, i told you smaller was better, now i just have to convince my ex girlfriend, LOL

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Wide Open Till You See God...Then Brake

 

I HAVE THE 1 3/4 SLP W/AIR ON MY 406. I BUILT A PRETTY MILD ENGINE, KEEPING THE STOCK TPI BUT WITH 24LB SVO INJECTORS (AT STOCK PSI), I DID ADD WORLD HEADS AND A HI FLOW CAT. CUSTOM CHIP NO IN YET. THE SLP'S WERE $510 DELIVERD (NOT COATED) THRU THE GROUP PURCHASE. THAT INCLUDED INSTALLATION KIT AND ADAPTOR FOR THE CAT. I HAVE ONLY BEEN DRIVING MINE FOR TWO WEEKS, BUT LIKE IT FINE. EVEN AT 2000 RPM, YOU JUST ROLL THE THROTTLE ON AND IT GOES RIGHT NOW.

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HERS 90 IROC-Z 350 TPI
HIS 86 TRANSAM 406 TPI