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nice roach.
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Discussion Starter #1 (Edited)
Im putting a 383 in my mud bogging/sand drag truck (86 toy xcab SAS) and was wondering what size header primary tubes should I be looking to get for it.

Background information:

4 bolt main 350 block with steel 3.75 inch stroke crank, 5.7 inch rods, 2.02/1.60 stainless valves. Hyd flat tappet cam lift .512 with 1.6 roller tip rockers, weiand x-celerator intake, holley 750 dual feed, msd ign(distributor, coil, box with 6500 rpm pill), th350, 3500-4000 stall, reverse manual valvebody, toy t-case, 4.10 gears, 36 inch swampers, vehicle weight @ 4k lbs.

I have spoken with a couple people with similar engines and they have said that 1 5/8" primaries arent enoughfor what they are trying to do. I have a set of headers that have 1.5 inch primaries and I am sure that these are too small. What have you all found that works and doesnt blow the budget?

Sorry this is so long but thanks for any and all help. :jester:

-j-rOd
 

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That kind of motor combo sounds like 2 in. primaries equal length custom made headers..... I gotta warn you 3500-4000 stall into a toy case = :nuke: from a "dead stop" launch... what axles are you gonna run? So many factors call me if you wanna talk about it......Tim
 

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nice roach.
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Discussion Starter #3
Shaker said:
That kind of motor combo sounds like 2 in. primaries equal length custom made headers..... I gotta warn you 3500-4000 stall into a toy case = :nuke: from a "dead stop" launch... what axles are you gonna run? So many factors call me if you wanna talk about it......Tim
Im running toy axles for now just because I have a bunch laying around, they are light and have good ground clearance. If I break the hell out of them then Ill build a 9 inch. I think Ill be able to hold a toy case together for a while on dirt but if not Ill go with something heavier duty. Who would you recommend to build the headers tim? Ill give ya a call sometime soon.

-j-rOd
 

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How much compression are you running ? And how much duration does the cam have?
 

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nice roach.
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Discussion Starter #5 (Edited)
Compression is right @ 10:1 ,nothing too crazy, its streetable but just barely. I dont remember the duration right off hand ( 230 or 240 degrees @.050" sticks out in my head for some reason but I'm not sure) Ill post a pic of the cam card when I get home.

Thanks,

-j-rOd
 

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Discussion Starter #6
Elcyboy20 said:
And how much duration does the cam have?

Heres a pic of the cam card.
 

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nice roach.
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Discussion Starter #7
Anybody else got recommendations? Comments? Suggestions?
 

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nice roach.
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Discussion Starter #8
Come on somebodys gotta have a thought about header primary size...... At least criticize something.........geez.:flipoff2: :D Im an engine building newbie tell me something that I dont already know er sumptin.

thanks fellas

-j-rOd
 

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IIRC, smaller tubes produce more low end torque, larger tubes are better for more higher revving apps. I would think you would want bigger tubes 1 3/4 or so. Check drag racing forums or Hot Rod. You basically have a SBC drag motor, so the 1/4 mile guys have all the info you need.;)

EDIT: Shoot, call Summit or Jegs, they should be able to tell you too!
 

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Discussion Starter #10
motorhead72k5 said:
IIRC, smaller tubes produce more low end torque, larger tubes are better for more higher revving apps. I would think you would want bigger tubes 1 3/4 or so. Check drag racing forums or Hot Rod. You basically have a SBC drag motor, so the 1/4 mile guys have all the info you need.;)

EDIT: Shoot, call Summit or Jegs, they should be able to tell you too!
Thank you sir. :D You advice is very much appreciated. Now I just gotta find headers that I can make fit a sbc in a toy truck that have big primaries. Im still not ruling out a set of imca style headers exiting out of the fenders. We'll see, I'll post update pics once I get my junk together.

-j-rOd
 

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jhama78 said:


Thank you sir. :D You advice is very much appreciated. Now I just gotta find headers that I can make fit a sbc in a toy truck that have big primaries. Im still not ruling out a set of imca style headers exiting out of the fenders. We'll see, I'll post update pics once I get my junk together.

-j-rOd
You are welcome! Good luck finding what you need!
 

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The biggest problem is getting headers to fit a toyota. The toyota below is 85 with 671 blower and the headers are from that catalog that sells all of the toyota conversion stuff they are spendy at around $500 but they are very nice headers and the fit well.

 

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Discussion Starter #14
Re: Primary sizes

IBJEEPIN said:
What heads are you running?
Nothing too special... cast iron chevy heads that have been reworked, i.e. 2.02 1.60s, good valves and valve job, no major hogging out of the heads so far as porting, just a small cleaning of casting flash etc, gasket matching, etc.......
 

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Discussion Starter #15
4x4realm said:
The biggest problem is getting headers to fit a toyota. The toyota below is 85 with 671 blower and the headers are from that catalog that sells all of the toyota conversion stuff they are spendy at around $500 but they are very nice headers and the fit well.

Do you know what size tubes those headers have? I checked their website but it was no help.

thanks

-j-rOd
 

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jhama78. That is my toyota 4x4 realm posted a pic of. The best advice i can give you is to buy a set of those. I have done everything else from build a set to buy sets and none of them have equeled to those. Thay shell out awsome HP ratings and its noticable. Thay will not leak since thay are so dam thick thay are straight up heavy. Awsome workmanship. Thay are in the northwest off road catologe. If you cant find any info on these let me know and I will get you the number to the free catologe. it has other awsome stuff in it.
 

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Discussion Starter #17
TEAM X-TREME said:
jhama78. That is my toyota 4x4 realm posted a pic of. The best advice i can give you is to buy a set of those. I have done everything else from build a set to buy sets and none of them have equeled to those. Thay shell out awsome HP ratings and its noticable. Thay will not leak since thay are so dam thick thay are straight up heavy. Awsome workmanship. Thay are in the northwest off road catologe. If you cant find any info on these let me know and I will get you the number to the free catologe. it has other awsome stuff in it.
I was looking at them back when I first started planning this project but damn they are spendy.... Anyhoo I dont have the newest NWOR catalog so if ya got the number for a free one thatd be cool. Thanks a bunch fellas.

-j-rOd

p.s. hey do you happen to know the diam of the tubes though?
 

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Ill look up the # tomarrow for ya. Ill mic the tubes for ya also.
 

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Discussion Starter #19
TEAM X-TREME said:
Ill look up the # tomarrow for ya. Ill mic the tubes for ya also.
Much appreciated man, Thanx:D :beer: :D

-j-rOd
 

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