Kooks 1 7/8 stepped to 2 inch headers to big
IMO, it is incredible overkill. I would go with 1 3/4. They are plenty for a built 346 on the jug. You will keep some torque staying with a smaller header. If you went to full length 1 7/8 you would lose some torque, possibly enough to feel a difference, but you would only "need" these on a extreme small cubic inch build. the step 1 7/8-2 are sufficient for large, high hp motors.
Are you thinking about the ones in the fs section? Me too. I'll sell you mine for the same price to get his. You want mine. 1 3/4's stepped to 1 7/8's. I'm stepping up to a bigger motor and need them. You need mine.
Stick with 1 3/4's. If you think you will be upgrading to a 402, 408, etc in the very near future, then you could get some 1 7/8's now, and still use them later with more cubes.
I have Kooks 1 7/8 stepped to 2 inch headers on my new setup, but thats a little bit more agressive. 402, Procharger F1C, ETP 245 heads, carb manifold..etc
I have Kooks 1 7/8 stepped to 2 inch headers on my new setup, but thats a little bit more agressive. 402, Procharger F1C, ETP 245 heads, carb manifold..etc
They are overkill and not needed for a stock cube motor but I have kooks 1 7/8" headers that I bought used for a great price on my Stock internal car. when I posted the same questions I remember guys saying I'd loose 25-30 ft lbs of torque and the car would horrible to daily drive because of this massive loss in torque. In reality though I noticed no loss of torque with the 1 7/8 Kooks with nothing but 1 chamber flowmasters clamped right onto the collectors which I was told would net an even larger loss of torque... lol! If I did loose torque it was all in low RPM ranges under 2500 rpm but I have a big stall so the car never sits at low rpms anyhow. If you have a stock stall or are an M6 you may feel a torque loss a lot more and find different results.
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Thread Starter
On The Tree
Joined: Nov 2006
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my plan is for 408 but thats after my current motor goes. I dont think that will be anytime soon, knock on wood. I understand that these are for bigger cubed motors, but i also know nitrous loves huge exhaust. plus i would be getting nearly brand new headers for a damn good deal. and for future reference i have a six speed car.
Do some research!! You will clearly see that those headers are to big for a 346 no matter what you are doing to it. The best headers yu can get for a 346 is a the 1 3/4 stepped to 1 7/8. What the **** am I lying? I already have a premium header. I'm going to a 427 or 440. Even at that 1 7/8 is all that anyone uses. If you dont want to listen then go ahead and buy them. I'll spend the same amount on a new set of ARH 1 7/8 and be very happy with them. You on the other hand will be like .. where the **** is my power!
Do some research and help yourself out. I dont give a crap what you do. I'll spend the same amount no matter what you do. I'm trying to help you.
Heres some more info for you. They have 3.5 inch collectors on them. Do you have a 3.5" Y pipe?
Do some research and help yourself out. I dont give a crap what you do. I'll spend the same amount no matter what you do. I'm trying to help you.
Heres some more info for you. They have 3.5 inch collectors on them. Do you have a 3.5" Y pipe?
Hey blanco, are those the Edelbrocks? Did you have move to those from 1 3/4? How'd they work out for you? ...I just put some on my bolt on car, but haven't go tthe y-pipe on yet and can't drive it anyways because of about a foot of snow all over 
If you ran those headers on a dyno you would notice a power increase on the top end on a large cube motor. But you don't drive on a dyno and rarely operate the engine at the high RPMs that those headers are designed to perform at. I would not bother with them at all on anything under 400ci, and then only on a track only car.
What's on your car now?? If you already have headers, keep them untill you actually get the 408 (if you do). If you don't and want headers that will work with thew 408, I'd still go with 1 3/4 as they are the best choice for the street in almost all circustances. If you want more than that (and you don't need it), get the 1 3/4 stepped to 1 7/8 headers. Headers larger then that will kill exhaust gas velocity which hurts torque.
Re'
What's on your car now?? If you already have headers, keep them untill you actually get the 408 (if you do). If you don't and want headers that will work with thew 408, I'd still go with 1 3/4 as they are the best choice for the street in almost all circustances. If you want more than that (and you don't need it), get the 1 3/4 stepped to 1 7/8 headers. Headers larger then that will kill exhaust gas velocity which hurts torque.
Re'
what cam? how much spray?
I'm going to say at minimum you need a 1 &7/8. remember any precious low end torque that you are going to lose from not having 1 &3/4, the spray will quickly give you back and the bigger primary is going to help you mph on the big end. FWIW, I picked up 1mph going from 1&3/4 to 1&7/8 with stage2 heads and an ls6cam and any torque that I happened to lose didnt make a difference anyway since I was only in those rpms for a fraction of a second waiting for the stall to flash. The longer I sit here and think bout it, the more I think you just go ahead and buy the 1&7/8-2" because I think you'll see good results with it. or maybe i'm just curious to see what they'll do lol. But seriously though, I firmly believe any ls1 with an adder no matter what the cube size will see positive results from having at least a 1&7/8 primary.
Steve
I'm going to say at minimum you need a 1 &7/8. remember any precious low end torque that you are going to lose from not having 1 &3/4, the spray will quickly give you back and the bigger primary is going to help you mph on the big end. FWIW, I picked up 1mph going from 1&3/4 to 1&7/8 with stage2 heads and an ls6cam and any torque that I happened to lose didnt make a difference anyway since I was only in those rpms for a fraction of a second waiting for the stall to flash. The longer I sit here and think bout it, the more I think you just go ahead and buy the 1&7/8-2" because I think you'll see good results with it. or maybe i'm just curious to see what they'll do lol. But seriously though, I firmly believe any ls1 with an adder no matter what the cube size will see positive results from having at least a 1&7/8 primary.
Steve
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