AU 4 litre, will they safely bore out to 60 thou and is it worth it?

[Stumps 384]

Pretty much what the title says, can the AU 4litre bore out to 60 thou, which would pretty much give it dead on 250 cubic inches.

 

Is it worth the effort going for 60 thou, I know crossflows and a lot of other sixes have no issues with a 60 thou overbore and it gives about 6 extra cubes on a 6, but is overboring the block really worth the effort?

 

Also does anybody have any recommendations for piston brands these days. Normally I would of just picked up some ACL's but seeing as they dont do that stuff anymore, what's the next best thing?

[Stumps 384]

*crickets*

[Tazvan 267]

I personally would rather stay as close to a standard bore as possible. It also depends on what you are trying to do, such

as, are you going for all out performance or a mild combination... also are you thinking cast, hypereutectic, or forged piston's?

There is a lot to consider when building engines... e.g. taking a block out to what is considered maximum, can bring on other

issues, like the cooling system may need to be upgraded and the possibility of split bores, and boring out to max also reduces

the amount of area for the head gasket to seal against, as the distance between bores is less...

Some 265 Hemi 6 blocks can be bored to 90 thou, taking it from 3.91" to 4.00", which all of a sudden opens up a more extensive

range of possibilities...

Sorry I don't have a direct answer to your question, just some food for thought...

[Stumps 384]

http://www.ozfalcon.com.au/index.php?/topic/1233-thoms-40l-thread/&

 

Been reading this thread, very interesting read indeed.

 

Seems all I need is an EF XR6 head to build thoms combo, got all the rest of the parts, pretty sure the XG cam is the 91DA cam spoken about in the thread.

 

Would come pretty close to getting the XB into that magical 13 seconds bracket I'm chasing.

 

 

[2redrovers 22,408]

Thom's thread is the business when it comes to those motors. Might even find the answer to your first question in there somewhere too.

[Stumps 384]

Is the XR6 VCT topend worth playing with as far as the head goes? or should I be looking for a different head like the EF XR6?

 

I have the correct EEC to suit the VCT with a 5 speed.

 

I was thinking of running a Barra ECU for extra tunability would it be worth going to an FG coil pack arrangement?

 

I have what I assume is the stock XG engine as well with everything needed to run that so swapping parts is doable for sure.

[Fingers 524]

From what I am aware, the only difference between the XR6 head and the VCT head is the VCT.

 

As far as the BArra ECU, pretty sure you would be better off with individual coils.

[Stumps 384]

5 hours ago, Fingers said:

From what I am aware, the only difference between the XR6 head and the VCT head is the VCT.

 

As far as the BArra ECU, pretty sure you would be better off with individual coils.

Is the AU tickford head any good flow wise.

 

I checked out my XG motor, it has a 94AB head which seems to be one of the better non tickford e series heads.

[Fingers 524]

I don't have any proof other than being told that the AU heads flow better than the earlier heads

[deankxf 21,644]

7 hours ago, Stumps said:

Is the AU tickford head any good flow wise.

 

I checked out my XG motor, it has a 94AB head which seems to be one of the better non tickford e series heads.

 

20 minutes ago, Fingers said:

I don't have any proof other than being told that the AU heads flow better than the earlier heads

@Thom any thoughts on VCT heads, AU tickford heads and the XG head above?
 

is the head even a restriction with a stock ish cam?

[Stumps 384]

from my understanding the difference between the 94ab and the 94dt (ef xr6 head) was the valve size, pretty sure they had the same port size, but I could be wrong.

 

I'd assume that fitting the larger 94dt sized valves to the 94ab head would bring it up to the xr6 heads flow rate.

 

Does any one know what the exact specs of the EA Falcon's cam is?

[Fingers 524]

I can find the cam spec

[Stumps 384]

12 hours ago, Fingers said:

I can find the cam spec

that would be awesome if you can.

 

I think something close to thom's 180rwkw's beast would be more than enough for the XB.

 

I'm pretty sure the XG engine I have has a 91DA cam in it, but I havent had it apart to check, but I was rebuilt by HM Gem a few years ago so who knows what it could be lol, I can only assume.