LS17000RPM

Mihovitz runs 6.5 at 217mph, what do the fastest LS1's run? The B heads come stock in every 96-98 Cobra and 93-98 Mark VIII. They are best for forced induction purposes as their combustion chamber is 222cc.

germeezy1

B heads are 96-98 Cobra 32V heads and 93-98 Mark 8 heads, good for forced induction because of there combustion chambers.

Sunset'01Z

iTrader: (10)

well isnt that neato lol.

fastest lsx i've heard of was a guy running like 6.80's at 205 mph with a blown/tt setup pushing 16xx hp. he posts on here sometimes, forgot his name.

germeezy1

The N/A Cobras flow better than people believe, I talked to HP about a TT system when I had mine and was amazed at how a little 4.6 could put out as much power w/o a whole lot of boost.


Robert's 2001 Cobra is bone stock except for the HP twin turbo kit, the gauge package and sub-frame connectors. HP Performance did the installation on this car, and Robert drove it 500 miles back to Dallas/Ft. Worth, TX, where he is from. The car pulled strongly on the dyno, registering runs of 479 rwhp / 498 rwtq @ 7 psi, 510 rwhp / 542 rwtq @ 8 psi and 517 / 530 rwtq @ 9 psi

And 9 psi isn't really anything on those motors, and these are with pump gas!
A good meth injection system and intercooler and even more power is possible on pump.

Black02SLPSS

iTrader: (5)

Hell for the cost of those heads would be half the funds i would need to buy an LS7 crate motor or build me a nice 408 or 427. And on a side note i bought my car for 9500 dollars and its just scary to me that i could go out and buy a set of heads that are damned near the same price of my car. Just my .02

Sunset'01Z

iTrader: (10)

as far as the heads go, i'm assuming the valvetrain is what makes the difference between a 2v 4.6 @ 8 pounds of boost making 415 at the wheels and a 4v 4.6 making 510 at the wheels with 8 pounds of boost.

i saw an 03 mustang gt with a kb blower on it making 415 at the wheels, needless to say, i wasnt impressed.

Sunset'01Z

iTrader: (10)

what about the 99-01 cobra heads? what's the difference between those and the B heads?

goodol'93z

iTrader: (14)

just my .02 cents on the video with the 406 sbc w/the 32 valve heads maybe the engine displayed such great throttle response because it didn't have a flywheel or flexpalte on it. just a thought

Sunset'01Z

iTrader: (10)

http://youtube.com/watch?v=t65VypaaR...elated&search=

video of that 6 sec ls1 powered camaro.. one bad bitch for sure

Ted J

iTrader: (4)

They are similar to a Hemi where they are in the middle of the combustion chamber. If you look at the valve cover off to the one side, on the LSX head pictured in the link in the first post of this thread, you'll see that the plug for the spark plug is off to one side a little.

HTH!

germeezy1

Really the only way to make a true 32V head is with a pentroof combustion chamber. I remember telling someone on one of my forums that my Northstar was more of a Hemi than his Hemi in his 300C. It started a huge flame war until people realized it was true.

germeezy1

A big difference between engine response on a dyno and in the car under load !

germeezy1

Remember that the 4V heads are the main difference in the engines, they allow the flow that actually lets them make power over 5500 rpm. And N/A its good for 60 hp PI to 32V. But the 4.6 2V heads are really setup for torque its one reason why some ford motors sucks so bad. OHC engines that are tuned to try to be OHV engines when they grow up. You end up with an engine like the 5.4 in the F150. Its a slug anyway you put it, slow to rev and a lower redline and power peak then the Generals OHV motors.

germeezy1

B heads are dual port heads that are better at low rpm and respond well to boost. C heads (99-01 Cobra) are tumble ports and don't respond as well at low rpm but scream at high rpm and respond well to being ported. Alot of people prefer the B heads when they build them because of the better mid range power.

Sunset'01Z

iTrader: (10)

i could understand using b heads over c heads then on a street car but why on a race car would guys use b over c heads? hardly ever in midrange on a strip..

germeezy1

Its more because of the combustion chambers and responding better to large amounts of boost. Most boosted cars don't need to turn extreme rpm to make power.

RussStang

Just goes to show you the magic an awesome porter can work on shitty heads.

How does it actually matter whether an engine is DOHC or not, in regard to how fast it can spin up? It doesn't. That engine revs up insanely fast because it makes extremely high horsepower numbers.

chuntington101

and there you have another great advantage of DOHC heads! you spend money on porting STOCK HAEDS rather than buying aftermarket ones and then getting them ported.

have a look at the inport market, EVERYONE is porting stock heads be it for race or street. there are very few aftermarket head about.

thanks Chris.

germeezy1

As far as production heads go the B and C heads are actually pretty good. When the 96 Cobra came out the LT-1 was in full force so they had to do something to make 1.1 liters less displacement engine make power.

ChucksZ06

iTrader: (9)

no one has mentioned the ZR1 32 valve engine. It made a whole 405 hp and ruined the handling of the car with the excessive front end weight. Tell me about a 4 valve engine that weighs 400 lbs and puts out 500 hp, almost that much torque, and is naturally aspirated. The fact that it is inexpensive and easy to work on are additional benefits. Ferrari's have the hp but no torque. The big mercedes v8s come close but are heavier and very expensive.