have you done this process of putting gt40p heads on?
what did ya end up doing to get them to fit?
readin back over it i think there was a comment about ya have to get e series extractors to fit gt40p heads

there is no difference in the way the bolt up, due to diference in the steering rack and intermediate shaft au specified exhaust manifolds will not clear in an e-series engine bay. im am in the process of doing gt40p heads into en ef xr8 and am using pacemaker ph4000's. they bolt up just fine and still clear everything in the engine bay. Due to different spark plug angles on the gt40 heads 90deg igntion lead boots must be used.

there is no difference in the way the bolt up, due to diference in the steering rack and intermediate shaft au specified exhaust manifolds will not clear in an e-series engine bay. im am in the process of doing gt40p heads into en ef xr8 and am using pacemaker ph4000's. they bolt up just fine and still clear everything in the engine bay. Due to different spark plug angles on the gt40 heads 90deg igntion lead boots must be used.

cheers mate

But you used the term "flow 400rwHP" which implies STP (standard temperature and pressure) conditions, however using a blower contradicts this as both pressure and to a lesser extent temperature are raised.

In fact you could follow the same logic and say that the crappy E6 heads should flow 400hp at the wheels, which is obviously a nonsense. But given enough boost it should be possible.

So under ideal conditions GT40P heads can actually flow 397fwHP give or take. This is approximately 335rwHP. In the real world you should hope to achieve somewhere around 350fwHP (about 300rwHP) if your parts combination is well matched to the flow characteristics of the cylinder heads. The more mis-matched the combination becomes, the further away from this figure you will get.

because a hole heap of yous have jumped on and dribbled so much s**t i can't tell where ya mouth is to your a** let me start again for those that have just jumped in

i had a set up in my 98 au xr8 that consisted of a VORTECH SUPERCHARGER a standard bottom end bar the cam gt40p heads i had 410-415 REAR WHEEL HORSE POWER dyno sheets that prove it was at the wheels o i get it your on about na then yes you might be right. i guess if ya add a pump you'll get more hp

Chill bro. I think everyone got that - with the blower you were making 400+rwhp. It's just that in your post at the top of this page, it looks like you're saying you'll disregard what you read in the Gregors manual and GT40Ps should flow 400hp at the wheels. In reading that post, I was under the impression (as I'm sure xafalcon was) that you believed the heads are capable of flowing 400rwhp. Generally, when people speak in terms of what a head can flow, it is always in NA form. Obviously, if something is boosted, then those figures can sky-rocket.

Not trying to have a go or anything like that, just trying to avert another thread turning to s**t like I've seen way too many times on this forum.

Tends to happen when most people talk in hypotheticals, this man has the sheets to prove it that they can flow 400rwhp wether or not it has a pump.

So id say if your not running boost then no it wont flow that BUT the max flow is still 400rwhp.


I understand you mate, i understood even reading your other post tho most people think they know all.. ah well.