Edelbrock 4.0L head soon to be available.

[jeepxj3]

1.91" Intake/ 1.50" Exhaust 55cc chamber
smaller chamber for higher compression ratio and more power?
'recommend appropriate intake and aftermarket exhaust headers for best performance gains'

I would like to see the flow numbers and 'back to back' dyno testing.
What valve springs? opening/seat and 0.500" pressures

[SilverXJ]

1.91" Intake/ 1.50" Exhaust 55cc chamber
smaller chamber for higher compression ratio and more power?

Yes

Found this leaked pic on another forum:

[SilverXJ]

Anyone want to take a guess on base price? I'll go with $995.00

I'd say around $1300.. maybe more at first.

[SilverXJ]

The 55cc combustion chamber on this head will bump compression above a stock 4.0l by .28 point. Add the .044" gasket and its .42 point. The head could probably be milled a bit to bring the compression up even further, depending on what grade of gas you want to run.

[jeepxj3]

The 55cc combustion chamber on this head will bump compression above a stock 4.0l by .28 point. Add the .044" gasket and its .42 point. The head could probably be milled a bit to bring the compression up even further, depending on what grade of gas you want to run.

That will be 9.4 to 9.5:1.
Hopefully it will run on a stock ecu tune.

Ideally they will do a 'top end package' like they do with other engines, head, cam, intake, but these usually only help power above 3500 rpm.

[SilverXJ]

That will be 9.4 to 9.5:1.
Hopefully it will run on a stock ecu tune.

The stock 4.0L HO has a compression ratio of 8.8:1. Then, 9.08-9.22. I don't see why it wouldn't work on a stock tune. Will it be optimal? Most likely not.

Ideally they will do a 'top end package' like they do with other engines, head, cam, intake, but these usually only help power above 3500 rpm.

Increased compression will help all around. It would be nice to have a full package. Especially the intake. Maybe if there is enough market response they could do a true roller cam, not like that mess that 505 offers. The good thing about Edelbrock's packages is that all the parts together usually deliver what they say it will or close to it.

[shawnxj]

anybody seen what type of material it's made from? it doesn't say whether it's aluminium or not

[jeepxj3]

My bad, .28 to .42, not .28 +.42.

[SilverXJ]

anybody seen what type of material it's made from? it doesn't say whether it's aluminium or not

I thought it was pretty obvious that it is aluminum.

[jeepxj3]

Maybe the 'Performer' Series is near stock with 1.91"Intake and 1.50"Exhaust for the CARB approval.
And then the 'Victor' Series will be with 2.02"Intake and 1.60"Exhaust and CNC porting, for more power and not CARB exempt.

[Jim K in PA]

I am a little confused by the bold paragraph that states the head was designed with the '91-'98 port locations. Are the '99-'06 port locations different? I thought the early and late manifolds were interchangeable on the head.

It sounds like the exhaust header is important to them, but I would like to know why. If this head is going to bump peak power, but only above 4k RPM, I am a lot less interested in it.

:EDIT: - derp - I looked back at the "Dyno" chart in the promo sheet, and it clearly looks like that is exactly where the improvement is.

I guess this comes down to how much more torque is made at lower RPM due solely to the increased compression that can be run using the same octane fuel as would be used with an iron head.

Price is going to be a huge player in the success of this product. If it comes in around $1000, it should be a winner. The higher it goes, the less so, IMO.

[SilverXJ]

I am a little confused by the bold paragraph that states the head was designed with the '91-'98 port locations. Are the '99-'06 port locations different? I thought the early and late manifolds were interchangeable on the head.

The exhaust ports are the major change. On the 99+ 0331 head (00+ on the XJ) the exhaust port floor is higher. The stock manifold reflects this. The sealing area between the stock 99+ exhaust manifold and earlier head is very small. The manifold also protrudes into the port about 1/8" creating a wall for the exhaust gases to hit.

I guess this comes down to how much more torque is made at lower RPM due solely to the increased compression that can be run using the same octane fuel as would be used with an iron head.

It would be nice to see this head used on a high compression build. Maybe a set of KB945s or custom pistons to push the compression up.

[Jim K in PA]

The exhaust ports are the major change. On the 99+ 0331 head (00+ on the XJ) the exhaust port floor is higher. The stock manifold reflects this. The sealing area between the stock 99+ exhaust manifold and earlier head is very small. The manifold also protrudes into the port about 1/8" creating a wall for the exhaust gases to hit.

Ah, thanks Chris.

It would be nice to see this head used on a high compression build. Maybe a set of KB945s or custom pistons to push the compression up.

Me too! But I am not too much of an early adopter, so I will probably wind up sticking with my '05 head and just port matching it and polishing the chambers. I am hoping to get the engine out of the truck around Christmas time, and have the block at the machine shop in January. Based on Troy's emails, this head will not start shipping until January. I may still consider it, depending on price.

And after looking at some of the other Edelbrock complete heads for V8s, I think the above estimate of $1300-1500 is probably more accurate than $1000. I guess we wait and see. I searched under the part #, but no one has it listed for sale (pre-order) that I can find.

[FlyinRyan]

If it is anything like their SBM head, the chambers will be larger than advertised. My .02

[SilverXJ]

I searched under the part #, but no one has it listed for sale (pre-order) that I can find.

LOL. I tried the same thing too and came up blank as well.