Right now I have Jet hot coated 1 3/4 LT headers and the project car is a VRE 383, LE3 AFR's and a Procharger D1SC, and the car is a daily driver.
We are estimating the car will make 650-700RWHP and I am wanting to know if I should do 1 3/4 to stepped 1 /78 or just do 1 7/8????

The next question is how is the fitment and where is everyone getting them??? I heard some guys had to do remote oil filters, smaller starters, and remove the heater box????
I have a Brand new GM LT4 starter and a 4L80E is going in the car, and I still have the heat. Just wanting to know my options and priced?
Thanks

 

check out kooks site and call them for advice. their headers are awesome and well worth the price. i remember reading somewhere w/ 1 7/8" you need to be running alot of boost/spray and larger displacement so that may be the route you choose. sounds like a killer build

 

Seems that that you can't even get a 1 7/8 from kooks?? Must be a Custom job? Where is the best place to buy the stepped headers I wonder?

 

Thunder Racing has Kooks 1 3/4" to 1 7/8" stepped headers.

http://www.thunderracing.com/catalog...&vid=4&pcid=52

This thread talks about Dynatech stepped headers as well.

http://lt1tech.com/cgi-bin/ultimateb...;f=19;t=000005

They're out there. HTH.

 

I know several places I can get them for but I remember seeing the 13/4 to 17/8 go for around $750 Brand new from somewhere??
I'll check out the dynatechs too, But I heard fitment sucked and I wonder if there stainless steel?? Still researching

 

I don't think you will see any gains from them over the 1 3/4

anything like that most of the time is going to be custom......Heddman used to sell them.

I would say your looking at $1200 on thelow end for someone to make them.

 

At 700 rwhp?

 

I know someone that was running 1 3/4...had a set of custom headers with stahl flanges 1 7/8 the car was 680 rwhp before.....and the same after.....didn't pick up at all at the track.

Every car is different tho.....

 

Sometimes generalizing from one specific occurrance may mislead folks less knowledgeable than you.

If someone were to do back-to-back testing of 1-7/8 vs 1-3/4 on a given 650-700 rwhp engine and found XX hp or lb-ft (peak or average) folks could then evaluate the $/hp cost of not leaving power on the table (or more specifically) inside the engine.

I'm not picking on you specifically: other folks, who should know better, preach the same thing without trying it. What works for 550-600 rw isn't always best for 650-700 rw. The engine knows.

 

As far as header fitment goes I have the stepped Kooks and they fit without any issues...I don't have an oil cooler, but everything fit with no problems...You do have to run the smaller AC PF454 oil filter or equivalent, though...Plug access is good and some have to grind a hair off the steering shaft bolt to prevent any rubbing...They are a great, quality piece...I'm told that the stepped design helps scavange very well...

At my power level, which is nowhere near your level, I picked up 1.5 mph and dropped .15 in ET switching from LPE shorties to the Kooks...Every little bit helps...

--Alan

 

Here you go...
http://web.camaross.com/forums/showt...hlight=headers

not trying to sway you either way, I would like to know where the limit is of a 1 3/4" header.


My uncle ran them and was running a 9.29-9.35 and had a set of big headers custom made and the car didn't change at all. His engine dynoed 800+(434 sbc in a 3400# 73 camaro, th400, 9")

 

The combination plays a lot into it... the camshaft specifically, if it's too large then you don't see as much of a gain, plus the exhaust port can work better with a smaller pipe than a larger one, all depends.

Bret

 

Alan where did you get your headers from about how much if you don't mind me asking?? Do you have the 3inch or 3.5inch collector??
Alan you have a small cam 383 like me so maybe that combo works well together?

Bret I am a small cam type of guy with a lot of lift so you think on my setup with a smaller cam the stepped headers would work better?

I have a buddy with a LS1 car that is running 1 7/8 and a 222/228 on a 115LSA on a 346 3400lb car with a maxed out D1SC running low 9's.

 

Hedman makes a set of straight 1 7/8 headers with 3.5 inch collectors for a LT1 car. I have a set on mine. If your exhaust system is maxed out from the header back with 1 3/4 headers I do not see how a bigger header will help. On the other hand, with a system like mine, 3.5 inch y pipe, 4 inch Mufflex, single in/out Magnaflow...I could see where it WOULD help the car.


Power adder cars "help" the exhaust out the pipe, Normally aspirtated cars are most sensitive to exhaust size.

My Hedmans had to be "modded" to work with power steering and the A/C box.



David

 

[QUOTE=T/A KID;4739596]Alan where did you get your headers from about how much if you don't mind me asking?? Do you have the 3inch or 3.5inch collector??
Alan you have a small cam 383 like me so maybe that combo works well together?

I got mine from F-Body Central in Baltimore during a buy in for around $800, plus around $200ish for the non catted aluminized Y...Collectors are 3"...I bought them with Joe Overton's recommendation and they seem to work well...I have since gone to a true dual system and have the 3" Kooks aluminized Y pipe sitting around if you decide to go that route...My cam is a 226/234 with lift a tick under .570"...

--Alan