does anyone no the power differences between an ed6 and ef6 the reason i ask is that my ed head s**t it self a week ago and managed to score a relativly new ef head for $150.

dunno exactly. i thought the only major difference was the plenum/intake between the two engines.

The heads on ed and ef are identical, the only real difference lies in the valve sizes, the ports are different slightly i think.

EF head will bolt on no sweat - the MPEFI manifold and exhaust will all fit up exactly as on the ED head - the ED rocker gear will also all fit aok. The difference lies in the rocker sill and possibly some internal differences.

I don't think the valves are any different in size between ED and std EF heads (EFXR6 has larger exhaust valves) - the rocker cover sill is different on the EF head - I know for certain that an EF Rocker Cover will fit ok on an ED head but I'm not sure how the ED Rocker cover will go on the EF Head (the EF rocker cover sill is broader) tho it should work ok - maybe a touch of silicon required at the corners of the halfmoon cutouts as the EF cutouts have rounded corners and may leave gaps with the ED rocker cover gasket.

Also, the ED rocker cover is secured with nuts which run onto studs which protrude from the rocker gear - whereas the EF rocker cover is secured with bolts - but the cover bolts are in the same locations and are the same thread as the ED cover studs - if you're reusing the old ED rocker gear then of course the studs will still be there - if you're using the EF rocker gear then it should be easy enough to swap over the studs.

I know that the EFXR6 head has different port design to the ED - the EFXR6 ports don't have built up "bosses" around the valve guides inside the ports the way ED head does - the guide just comes out of a smooth wall and protrudes into the port. Not sure if the std EF head does this too.

The other major differences between ED and EF engines are that the EF runs higher compression - ie. std EF comp = 9.3 (EFXR6 = 9.35) and ED comp = 8.8 The EF of course also has the BBM - and has multicoil ignition (no dizzy). The std EF compression is acheived with different pistons to the ED - and the EFXR6 I think must also have a slight head shave. Also the EF crank is different to the ED and the EF uses hydraulic engine mounts as opposed to the ED's simple rubber ones. EF also has serpentine belt on the front as opposed to the ED's various belts.

Personally if I was using an EF head on an ED engine I'd grab an EL rocker cover (and the bolts to hold it on of course, plus a new seal) - that way you'll have the right shape for proper sealing plus the EL cover will have plug lead clips in the right places (an EF cover WON'T).

Ah,... I should add that I actually have an EF XR6 head on my ED engine - but I'm using an EF rocker cover (had to silastic the plug lead clips into place) - I've been meaning to grab an EL Rocker cover for ages.

The power difference between the ED and EF/EL is around 10kw and 20nm torque

nice to know someone can at least answer the question...

145kw v 157kw not sure on torque figures

Well he'll probably need the BBM, thermos and ECU to get that difference, not just the head!

Yeah - I should have made myself clearer - there is a difference in power but it's NOT IN THE HEAD - there are differences in the rest of the engine and induction etc.

I should ADD here that when I fitted the EFXR6 head to my ED engine, no I did not feel any NOTICEABLE difference - I'd guess there might be something noticeable on a dyno - most likely in the top end (because of the bigger exhaust valves).

355nm torque in the EL, and roughly 335nm in the EB/ED

Power Outputs:

Standard - 157 kW @ 4900 rpm / 357 Nm @ 3000 rpm.
(up from 148 kW @ 4500 rpm / 348 Nm @ 3750 rpm in ED)
XR6 - 164 kW @ 5000 rpm / 366 Nm @ 3150 rpm.
(up from 161 kW @ 4600 rpm / 365 Nm @ 3650 rpm in ED)


taken from http://www.trueblueford.com/EF_engine.html

348Nm from EBII, ED should be about the same.