Header size for 500RWHP?
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From: Readsboro, VT
Header size for 500RWHP? I'm building a 402 with LS3 heads, and aiming for 475-500RWHP. This is going into my IROC, and header choices are very limited. All that's available is 1 5/8" long tubes, 1 3/4" long tubes, and now Hawks is offering 2" long tubes, but only as part of a complete kit, and for a TON of money.
My question is... what is the optimal size for my application (I had guessed 1 7/8"), and secondly... how much power am I sacrificing by going down to 1 3/4"?
A third option is to have the headers custom made, but I'm guessing that'll be prohibitively expensive.
My question is... what is the optimal size for my application (I had guessed 1 7/8"), and secondly... how much power am I sacrificing by going down to 1 3/4"?
A third option is to have the headers custom made, but I'm guessing that'll be prohibitively expensive.
an 1 3/4 tube can flow alot more air than people give credit . i only have 1 3/4 and my less than optimal 408 puts down 536 rw. only real gain would be on the jug but mine does a decent job on nitrous as well. ofcourse that is just my opinion so take it with a grain of salt. if it is alot more money for a larger tube spend the money elsewhere.
1 3/4 will work and be fine. You might be leaving some power by not having larger headers but all racing/hp comes down to the dollar. How are you wanting to spend to be fast lol.
I have seen more than a couple flow bench data sheets with 1 3/4" pipe vs. 1 7/8" pipe. Up to .400" lift typically they are even, and after .400" lift 1 7/8" is about 3-5cfm better.
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I think you would be better off buying a set of BB chevy headers (if available for third gen) and cutting the flanges off and have LS flanges welded on. I remember reading somewhere that this is possible on earlier cars.
Just a thought.
DJ
Just a thought.
DJ
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If i was buying new and Hawks sells them separately I'd seriously consider the 2". I've seen claims that they lose nothing over the 1 3/4"s but gain up top on some of the fifth gen boards. I'd also research it moer than i have before I bought em. Fitment etc. The 1 3/4" original design SW's pieces are amazing IMO but I think I got extremely lucky and landed a sweet pair. A friend ordered new ones this yr and they were nice... But not perfect
Ran 9.94@139 on a 364 with a 200 with our off the shelf 1 3/4". If you have a 4400 stall converter and a light race car bigger headers will help. But if your not an all out race car smaller header will give better gains across the board and on the street.
Ran 9.94@139 on a 364 with a 200 with our off the shelf 1 3/4". If you have a 4400 stall converter and a light race car bigger headers will help. But if your not an all out race car smaller header will give better gains across the board and on the street.
Way I see it, if the car sees mostly street and open track, the torque of the smaller diameter headers will offset the high rpm power. If you're going to run high rpm, big cubes, or big hp, then larger diameter primaries. Same with heads. Absolute flow numbers are just for bragging. Velocity rules.
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From: Readsboro, VT
A lot of people are claiming that there is absolutely no loss of torque by going to larger diameter primaries on the LS motors, that's why I was looking to the bigger headers in the first place.
Like mentioned above... without some dyno numbers, who really knows, but in either case, it seems that the 1 3/4 will suit my car just fine.
Like mentioned above... without some dyno numbers, who really knows, but in either case, it seems that the 1 3/4 will suit my car just fine.
