J-Rod

I'd be interested in seeing what it would do with a shorter primary and a slightly bigger tube diameter. I think the current LG headers are ideal for the 346, I'm just curious if the 427 needs a little less primary length. It'd be interesting to see if this has any effect. I'm alos interested to see what all GM has left on the table in terms of power.

Checkmate

iTrader: (2)

WOW. That is awesome.

Do me a favor, please tune a stock z06 and post before/after numbers.

DAPSUPRSLO

iTrader: (14)

Keep the R&D comming guys, great work. I've been saying it all along, 750fwhp from a cam and headers swap will be no problem for this car.

OUTLAWZ RACING

iTrader: (9)

I hate to hijack but man lg motorsports is the shizznit i dynoed my car there in 2002 i bought it brand new in georgia with only a lid and muffler slowmaster it made 339 hp 342 TQ those guys told me i had a factory beast and being a newbee to ls1 gave me two pages worth of stuff to do good stuff LG oh can i purchase your c6 race car??
ok shut up and let me dream!!!!!
oh can you tune 05 goats??

Fulton 1

iTrader: (9)

I'm assuming that the primaries tested were 1-3/4"? If so, I'd also be interested to see what 1-7/8" would do.

And to think that some of the many "experts" on the Corvette boards were certain that there wouldn't be much at all left in the LS7 from the factory

I think there is a great opportunity for a killer cam/header/tuning package for this application. I know I'll be all over it when my time comes.

abadss

iTrader: (4)

wow, impressive #'s. with some tuning this thing could be near the 500rwhp mark with just headers?! this thing is going to be a true monster

Big-DEN

I guess I can't say nothing. The LG is prolly a 1 3/4" to 3" collector affair.

We know for a motor this size, 1 7/8" into a 3.5" collector is a better deal.

Still. With the LG long tube a air box and some tuning this is going to be a beast.

Now somone needs to flow the intake and flow the intake and heads attached. My guess is the intake and heads together do around 325CFM bolted together. That the intake by it self does somewhere between 325-350CFM.

Someone is going to find over 400CFM out of the heads with increases at all valve lifts over .200"

Fulton 1

iTrader: (9)

Just thinking out loud here, but isn't it fun to not only see this potential, but then to realize that its available in a 3100lb car that already comes from the factory with "supercar" handling and braking? Good times.

Nine Ball

iTrader: (38)

very nice results from just a header swap! It won't take much to clear 500 rwhp, but that is expected considering this is a 427ci and has better flowing heads/intake than we are used to. I'm sure some guys will be hitting 600 rwhp with the right combo pretty soon. I can't wait to see it!

I'm sure the GM guys that hang out on this site are reading this thread and smiling. Good work guys!

J-Rod

As I said, I'd like to see how the 427 responds to 1 7/8" primary that is a bit shorter than the current LGM longtube headers. I'm guessing there will be some HP there with no major loss "under the curve" in terms of Tq.

I know that on Joe Herrington's 427 C5 car that I drove, a Fast 90 and a set of 1 7/8 headers were worth 60+HP over an LS6 and 1 3/4" headers.

The car went from 497 rwhp to 556rwhp and 500TQ to 544 TQ

Car dynoed around 526 or so just swapping to a FAST, Joe then tried 4 sets of headers and dynoed each time the ones that showed the best gains were the 1 7/8 that got the car to 556rwhp.

The header length math on the 427 seems to indicate a shorter primary length, and a bigger tube for optimal power.

As for the heads, I think you could increase peak flow, but Chapman spent enough time on the heads that I think porting them would be a waste at this point. The heads were optimized in alot of areas (Cross section, port size, flow, etc...) Sure, maybe you can get 400CFM @ .600 but what happens to midlift???

I think when folks start messing with the heads they are just going to slow cars down at this point. Too many folks in it for numbers rather than understanding one point on the flowsheet doesn't make for an ideal combo. See Tony M. post on his 383 test and look at the area under the curve on the middle cam versus the big cam if you need a prime example.


As for the GM Team... You guys totally rock.... Way to go guys!!!

scottyballs

iTrader: (3)

the mufflers might open up @3500 but I would like to see what it has with out them cats

Worm

iTrader: (2)

Very nice.

fredo92

Very nice....I'd be interested to see what it's doing today (thursday) since it's about 65 degrees this morning.

Adrian87GN

iTrader: (5)

No kidding!! My car was a whole new beast on the way to work this morning!! The first really cool morning since I've modded the car

Big-DEN

J-rod.

The heads have 2.20" intake valves in em. the heads you speak of have 2.08 or 2.10" intake valves, I know there is more flow in these heads with increases at all lifts.

Chapman designed them for this application with some margin for increases but not a stronger app. I'm sure somoene will find the 400CFM out of these with increases at all flows from .200" and up.

Someone will find out for sure enuogh.

NOSjohn

iTrader: (9)

Great results ! When is the G7-X going in ??

fotoboy

iTrader: (1)

Can I love a car payment the way Ilove this car!?

J-Rod

Unless you have spoken with Chapman, then what you are saying contradicts statements he has already made. John B spoke to him at length and his response was to leave the heads alone.

NOSjohn

iTrader: (9)

To finance $70,000 (taxes, title, tag, etc.) for 72 months at a very low rate of 6% with ZERO down, you're looking at a payment of $1,160.10 per month. More or less depending on term and money down. I would NOT love that payment.

Swang

iTrader: (3)

wow....i appluade the GM boys on this one. awesome...AWESOME job. has any auto magazine raced one against a viper? all i can say is wow...