Thats not exactly correct...the original GT40X head assemblies where x303 (64cc chamber) and x305 (58cc chamber), and these still exist in the Ford Racing Parts catalogue.

Since late last year, the catalogue also lists an x306 (64cc chamber) and x307 (58cc chamber), with the same description but for the addition of this comment;

Designed to be used on the M-6010-BOSS302 block with head gasket M-6051-CP331

Not sure what exactly the difference is, but it would be nice to see the old and new castings side by side to see if there is any difference in ports/chambers/deck thickness/casting quality etc....

The casting quality on my x303 heads where pretty crappy to say the least. I got them for cheap, but I regret not just waiting until I had the extra $1000 to get some AFR's.

t2te50, have you got the heads yet? Any chance you can pull the valves out of one of chambers and post some pics of the ports bowl/short turn etc...? Cheers

This is what the FRPP catalogue says about the M-6051-CP331 head gasket;

- Set of two gaskets with pre-flattened copper wire combustion ring
- Gasket bore is 4.100
- Exhaust side is straight to accommodate FRPP block water passages

Well, actually you order an X303 part number to get two X306 heads and X305 to buy two X307's.

We're getting off topic but check the Ford p/n link for M-6049-X303's and same with X305's and the others

http://www.fordracingparts.com/parts/pa ... Field=2601

http://www.fordracingparts.com/parts/pa ... Field=2603

Both p/n's specifically indicate sold in units of one, not a pair and the package weighs 27lbs (ie one) and costs $625 again for one

X306's and x307's are different heads although without close examination it's unclear in what manner. They are basic GT40 turbo swirls whereas the X303 and X305 are GT40X "Xtra performance" Turbo Swirls.

Check this link.

http://www.fordracingparts.com/parts/ca ... er%20Heads

xr8ute.

Yep I originally had X303's and their porting etc is not in the same league as AFR's, which along with the Tickford mild cam will make 13.8 probably out of reach .

Lets not play a numbers game guys, ford changes its part numbers like a chameleon and yet the part may be no different??? Go figure . Personaly a milling doesn't require a different part number!!!

Actually the cam has .490 lift with 1.72 RR so don't underestimate. It's the EB GT camshaft.

XR9UTE how does porting MAF vary load output if the actual sensor passage/port is left unmodified??

I thought the TPS would be faster then a MAF at relaying a signal back to the ecu because it doesn't have the reversion factor etc, its a clean switching signal???

the EB GT was revised to 192kw, and i highly dount that you will get a 13sec pass, given that a mate of mine has a T2 TS50 with a Herrod Cam, Zorst, Chip and some other work and cant beat a 14.6.... he has 185RWKW

Who here can do a high 13/400m and still get
10.0/14.5l, higway/city fuel economy?
NO ONE!!!!!!!!!! I'll be the first, I hope

You'd need better than a high 13 to shame XH5LWEPN wouldn't you? I know it's just numbers, but it is what it is...

Load calculations are thrown out because the sample tube will now be sampling a smaller fraction of the total airmass. The MAF transfer function is programmed into the EEC which means even though more air is flowing the EEC doesn't know it. Therefore the load calculation is wrong.
MAF is faster because in simple terms it is being measured many times per crankshaft degree. The MAF doesn't care about reversion it measures the flow whichever way it goes. There is a backflow correction map where you can account for this.
All signals except MAP(or BAP on early EB 5.0) are analog and are then converted to a digital form in the EEC.
If you think about it the speed at which you can stamp on the throttle it is actually extremely slow in terms of time when compared to the calculations occurring during any given crankshaft degree of rotation. Therefore as I've mentioned before it(TPS) is rather unimportant in the scheme of engine operation.

Put the high volume oil pump back on the shelf? Why My engine makes good power between 5-6000rpm, were the stock pump starts to taper off.

I love all the pesimistic chatter going around, not that I wouldn't be used to it being an AU Falcon owner .

I think many on here forget that my old engine ran a 14.4 with just a single 2.5 inch exhaust and HM headers. Not to mention it had 150,000 km and was an ex WHEELS, MOTOR mag thrasher.

My engine makes good power between 5-6000rpm, were the stock pump starts to taper off.

What do you mean taper off and how do you know that ?

HV pumps are really only required for "road racing" engines where bearing clearances are higher and constant high rpm's are the norm. With stock clearances you are not going to get any additional oil flow as street clearances will only allow x amount of oil flow anyway.

You also need to use a stronger oil pump drive as insurance as these pumps put additional strain on your cam gear with the risk of also flogging you distributor gear, all for no real benefit in a street engine other than you also lose a few kw's, which is not what you are trying to achieve .

But many still use them thinking it means better oiling etc etc, but none of the top street /strip engine builders here and in the US do. There are also some that say this extra flow pressure build up could cause bearing distortion issues in engines with normal street clearances.

But just the extra strain on the cam and distributor gears and the loss of a few kw's is more than enough reason to not use them when they are not needed for street applications and 6000rpm is also mild rpm .

I love all the pesimistic chatter going around, not that I wouldn't be used to it being an AU Falcon owner

We're just pulling your chain but it will be a miracle

Well judging by most of us drive our cars would it not be benificial to have a HV oil pump even if it is not fully necassary no doubt this car will see the track for a bit of High rpm flogging as I have seen it done in the past.

Why, when it's absolutely unnessary as all you are doing is putting extra strain etc on your distributor and cam gears for no gains. The stock pump flow is MORE than adequate for these modified street engines along with oil quality.

I assume you have pre primed an engine using a reverse rotation drill on the oil pump and felt the torque the standard pump requires. The HV is way worse. I'm currently building up a new 347 engine with more mods than described here and it will have a new stock volume Mellings

But if it makes you feel better to sacrifice a few kw's and risk these gears etc for no benefits then go for it but make sure you also fit an upgraded oil pump drive, which is even good insurance for a stocker

When the HV pumps first surfaced we all thought they were a necessity ( even I got on the bandwagon back then and used one in a heavily modified 351C) but that has now been disproven along with a lot of others
.

I second all of the above sentiments.

HOWEVER!

Its your engine, to build as you see fit. If you feel the factory oil pump is inadequate, then replace it.

I spoke to a wise old head today and he told me to avoid the high volume oil pump due to load on gears/motor and extra heat.
The AU3 XR8 has an oil cooler and still uses standard pump? What about if I put a Z9 filter on to increase oil capacity?