Does size matter?

[SouLRioT]

No, No, not that. But some members recently have stated that you only have one size kit now. Which one is it? The 1 5/8" x 2.5" OR 1 3/4" x 3" ?

[Bluerauder]

No, No, not that. But some members recently have stated that you only have one size kit now. Which one is it? The 1 5/8" x 2.5" OR 1 3/4" x 3" ?
This just begs for a smart a$$ reply. I will resist the temptation.

[03SILVERSTREAK]

This just begs for a smart a$$ reply. I will resist the temptation.:confused: :confused: :confused: :confused: :confused: and wanting to inquire :cool:

[03SILVERSTREAK]

:confused: :confused: :confused: :confused: :confused: and wanting to inquire :cool:Never mind-I got it...

[FiveO]

The Kooks headers only come in one size now, per Nick and my phone conversation with him last week...

1 5/8th x 2.5"

[CRUZTAKER]

2.5 inches baby...not big enough for New York, but big enough for the average bear!:cool:

[SouLRioT]

thanks five-O

[jrzygrl]

This just begs for a smart a$$ reply. I will resist the temptation. WIMP!!!!

DARN!!! I was hoping it WAS that kind of thread...... :D

[Bluerauder]

WIMP!!!!

DARN!!! I was hoping it WAS that kind of thread...... :D
:lol: Now, let's not be calling names ... or casting aspersions. I backed off 'cause everything seemed to end in ....
:censor: :banned: :bigcry: You're right, Lynn, I wimped out. Sorry.

[03SILVERSTREAK]

2.5 inches baby...not big enough for New York, but big enough for the average bear!:cool:Yogi Bear ? :D

[BillyGman]

uhmm, back to the original topic boys..........

2.5" diameter collectors w/ a 1.625" (that's 1 5/8") primary tube diameter is just right for a V8 engine that's as small as a 4.6L (281 cubic inches). Unless you're going to be spitting out 600 RWHP or better, a 350 engine or smaller will lose low-end torque by going w/anything bigger than 1.625" primary header tubes. You would have a bit more top end power, but it would come at the expense of low-end torque. And since the Marauder lacks low-end torque from the factory as it is, you wouldn't want that since it would defeat the whole purpose of modifying your car. And that goes for N/A engines as well as S/Ced ones.

So I'm sure that has something to do w/Kooks downsizing to the one size of headers for our cars.

[Cobra25]

No, No, not that. But some members recently have stated that you only have one size kit now. Which one is it? The 1 5/8" x 2.5" OR 1 3/4" x 3" ? What do you mean ( No,No, No, not that.) Size does matter! :rock:

[1 BAD 03 MM]

I recently read in the Sean Hyland Motorsport book that the old 1-5/8" vs 1-3/4" debate was mute on the 4V Heads. According to SHM the 1-3/4"x3" were worth 7-8 Hp throughout the RPM range on th 4V motors. He says this is because of the flow characteristics of these heads, not the cubic inches. :burnout: :burnout: :burnout: :burnout:

[BillyGman]

Feel free to correct me if I'm wrong, but to my knowledge the bigger size headers were the only ones that Sean Hyland offered for Marauders. So read between the lines....... as for me, I take their claim w/a grain of salt. Those headers that Sean Hyland sold were infact manufactured by Kooks for Sean Hyland. And Kooks no longer offers them in that bigger size for Marauders that they made for Sean Hyland. So what does that tell you? Draw your own conclusions. I've drawn mine. Getting 7-8 HP more wouldn't even be noticed while you were driving anyway, so this isn't even worth any debate.

If you want to base your claims on sean Hyland's book, then all I can say is thanks for the info, but that just doesn't hold enough weight for me. My claims are based on experience w/different exhaust deviations w/the 73 Vette I had for 6 years which had a 350 engine. Yes, that engine had 16 valves rather than 32 valves, however I also had installed AirFlow Research ported cylinder heads on that engine which had 2.02" intake valves, and 1.60" exhaust. So despite the airflow characteristic claims of Sean Hyland concerning the 32 valve engine, you can't tell me that the 4.6L 32 valve cylinder heads will out flow a pair of AFR 195 cc ported cylinder heads on a 350 engine. Because I cannot see that being the case at all.

There's also no way that you can say that displacement has nothing to do w/airflow characteristics, because it's all related. Sure, a 32 valve cylinder head will flow better than a 16 valve head will on a motor of equal displacement. But that doesn't mean that no matter how much the displacement is of any engine that you might choose to install those same 32 valve heads on, that the engine in question would outflow any 16 valve engine regardless of the displacement. It's all related, and you must take into account all of these factors. NOT just what type of heads are on the engine.

But if you choose to debate w/me about that, then you best tell me what the intake airflow CFM rating is for the Marauder cylinder heads at .500" valve lift. Because I can tell you exactly what the AFR rating is for the heads I had on my Vette.

[nick filippides]

Guys, Most of the theory that went into the design of these headers originated from our Cobra 4V designs that have now been thrashed on and dyno'd to death for years. We've learned that all but the most radical Cobra 4V's, including those with superchargers, responded really well to 1-5/8 headers both on the dyno and the race track. We originally prototyped Marauder headers for Sean Hyland and all our initial production runs were 1-3/4" primary headers. Though most tuners and/or engine builders have their own theories on header design, we couldn't run from the fact that Cobra's with 600 plus rwhp were performing flawlessly with our 1-5/8 headers. Add to that the fact that Marauders are a good deal heavier than Mustangs and it made it a no brainer. Sean Hylands 1-3/4" headers may be just the ticket for some of the high hp supercharged race engines he typically builds but we feel 1-5/8 is where 99% of Marauder owners need to be. The proof thus far has been in the proverbial pudding. Nick "Kook's Headers"

[BillyGman]

That's just what I suspected. Well we've heard it straight from the expert. Thanks very much for your input Nick. BTW, let me say that the headers you sold me are great as is the complete Kooks exhaust!!

[SouLRioT]

Thank you Billy and Nick.

[1 BAD 03 MM]

But if you choose to debate w/me about that, then you best tell me what the intake airflow CFM rating is for the Marauder cylinder heads at .500" valve lift. Because I can tell you exactly what the AFR rating is for the heads I had on my Vette.

Don't want to debate, just stating some info I had read.

I found the flow numbers, it compares 2003 4V heads to 1999 4V heads.


Lift------2003 Exh------2003 Int------1999 Exh-------1999 Int
0.050-----35------------46------------28--------------35
0.100-----74------------95------------68--------------87
0.150----105-----------128------------99-------------118
0.200----126-----------161------------121------------153
0.250----146-----------182------------136------------184
0.300----159-----------226------------145------------204
0.350----165-----------245------------151------------218
0.400----171-----------259------------153------------223
0.450----173-----------262------------156------------228
0.500----175-----------266------------158------------231
0.550----176-----------268------------159------------231

What are the flow numbers on your AFR heads? I was thinking about getting the AFR 165's for my Small Block Ford (306). I hear they are worth 100HP over stock Ford pieces.
An interesting link: http://www.modfords.com/forums/showthread.php?t=3050

[BillyGman]

Hey, some good info there!! I'm in work now, but I'll have to look up the flow #'s for ya when I get home.I remember a CFM flow rate of 280 for the 350 engine, but I think that was at .600". I was very impressed w/those cylinder heads from AFR, however I gotta tell you that their claims of 80+ hp gains over stock heads are inflated as are some other aftermarket companies claims. But I do think that they're some of the best cylinder heads available for street cars.


In my experience so far, the only mod that will give you gains like that and even a little better is a S/Cer or NOS (in other words some type of forced induction).

[BillyGman]

Yep, it's 282 CFM @ .600" lift (intake) and 275 CFM @ .500" Lift for the 195cc small block Chevy heads. But as far as the small block Ford heads that AFR offers, you can go w/the the 165cc heads, or if you want to focus more on midrange and top end power, then you can go w/the 185 cc ones. They flow 267 CFM @ .500"



Here's a link to AFR's site where you can see all the specs for their cylinder heads.....

http://www.airflowresearch.com/