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Old 11-19-2012, 11:04 PM
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you really think im leaving 50HP on the table with the block huggers??

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Old 11-19-2012, 11:34 PM
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With the way the motor is know what is your HP/TQ estimate

and what with a 750DP and longtube?? would you use 1 5/8 longtube?
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Old 11-20-2012, 12:03 AM
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WOW!!!! Why dont you tell me what you really think. Im asking because I DONT KNOW. isnt that what this forum is all about?? I am jsut trying to figure out how much is to be lost. If I go by your theorys id be into this motor for 25k. If you asked me a question I thought was "not rocket science" I would never speak to you or anyone that way. I would answer and try and be as helpful and friendly as possible. Im embarrassed to call myself a canadian.
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Old 11-20-2012, 08:28 AM
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exact header tube size and length is hard to determine. similar formula as an intake manifold except the other end.
A 4 into 1 header is like a single plane intake,it will make more power at a higher rpm than tri Y headers.Try Ys act like a dual plane with the bottom end increases starting at a lower rpm and rolling off peak powers sooner.
Tube size,smaller tubes scavenge the head sooner but will not have enough volume at higher RPMs or on bigger displacement engines.
some engine builders will generalize and say you need 1 5/8 primaries for 375 hp or less and 1 3/4 primaries up to 500 hp,after 500 hp you might need 1 7/8 primary pipes.
this type of statement is ok at best,or a starting point. There are a lot of ponies left on the table because people buy a $200.00 set of headers that fit 5 different cars,then spend 10k on stroker engines with big cam/heads and wonder why there engine makes ok but not spectacular power

choosing perfect headers is very complicated and almost always over looked
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Old 11-20-2012, 11:30 AM
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Thanks for the great info Fbirb. I really appreciate it. This is my first engine build so im kinda learning as i go. I had no idea block huggers were such a power killer but know i do That is a good plan. I think i will cut apart my exsisting headers to make long tube. I have measuered the primarys and they are deffinatly 1 5/8 od. I have a freind that will most likley have a 750 he will sell or trade me for.

Again, thank you for the very helpful info.
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