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 Post subject: Header recommendation
 Post Posted: Tue Mar 17, 2009 6:04 pm 
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Trying to help my cousin out. He picked up a 396 BB, that according to the engine builder is supposed to be around 600HP. He's been told that it needs 2 1/4" primary headers. To me, that's a bit big for a small inch BB. I don't remember specifics about the engine but it has closed chambered heads(which I've been told don't work as good as open) that have been ported and polished. I don't know valve sizes. Any help would be appreciated.

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Trevor

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 Post Posted: Tue Mar 17, 2009 6:14 pm 
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Is this a naturally aspirated engine if so i would opt for a smaller header. It sounds like to me that the engine builder is trying to inflate the hp numbers. I dont see a 396 with closed chamber heads making anywhere near 600 hp

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 Post Posted: Tue Mar 17, 2009 6:41 pm 
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Even with square port, closed chambered heads, the 396 would be a little hard pressed to make 600hp. Maybe with 14+ compression and alky. I suppose you could use NOS to get there, but I don't think thats what the engine builder was saying. It could use the big tube headers, but not really use them well untill you wound the snot out of it. A smaller tube header for a street motor might kill off 10 or 15 hp on the big end, but the gains of low end torque will more than make up for that small loss. Unless he can get a great deal, like real cheap or free, I would go a little smaller on that motor. The smaller tubes will fit around things a little better too. Just my opinion.

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 Post Posted: Tue Mar 17, 2009 7:17 pm 
 
I would go with 1.75" tubes, I ran those on my .030 over 454, stepped up to 2" on my 505 which is making in the neighborhood of 650-675hp. 2.25" is way too big for a n/a 396.


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 Post Posted: Tue Mar 17, 2009 7:44 pm 
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James no need for you to reply to this post. It's big block stuff. You wouldn't understand. :lol:

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 Post Posted: Tue Mar 17, 2009 8:39 pm 
 
AlteredMopar wrote:
James no need for you to reply to this post. It's big block stuff. You wouldn't understand. :lol:

I dont respond to BB drool :lol: :lol: :lol:


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 Post Posted: Tue Mar 17, 2009 8:44 pm 
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i only run 2'' tubes on my 540 alky motor...i'd go with what bob says 1.75

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 Post Posted: Wed Mar 18, 2009 6:20 am 
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Thanks everyone! I'll pass this along.

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