4.0 P38 vs 4.6 P38

[kiwicar]

I am pretty sure it is the same one as the MG, it is, for an ohc v8 pretty simple, there is quite alot of tuning stuff around for them, new cams are sensible prices. It makes between 215 and 260 bhp and 250 and 300 ftlb torque, in standard form depending on spec, have a read
http://en.wikipedia.org/wiki/Ford_Modular_engine
For £600 with a transmission and all ancileries, if it is running, has signs of oil changes and does not smoke or rattlet hen £600 is very cheep 200+ bhp territory. It is ford V8 bell housing so it will take all US ford manual V8 boxes (mustang T5 is probably a good start). Beyond that is is adaptor plate time, probably the toyota supra box would be logical as I think the engine and box are put together in Australia quite often.
As Eliot says there is a lexus on here for £350, bit more work but I think the toyota box will bolt on once you have sorted flywheel and clutch, you would need an ecu, probably extra efi of vems would be a good start.
Best regards
Mike

[marko10010]

If you want to build an engine that spends alot of time at wide open throttle and at high revs in a lighter car then I would base it around a 3.9 and a bottom end brace with studs unless you can find one of the very rare 3.9 cross bolted blocks. the larger journals in the 4.0 and 4.6 blocks cause more friction and hence sap power and I believe allow more flexing around the bottom of the cylinders than the 3.9 block. If it is for a range Rover comp safari or similar heavy car then go for the 4.6 but still brace the block as I think the block is too flexable for the stiffer crank and use an auto box with a manual valve body and higher stall converter as this will save the engine from shock loading.
Best regards
Mike

It looks like I may have a chance to buy a 3.9 RV8 out of a sd1 rally car. I don't know the exact spec of the engine yet, but from what I hear it's fitted with all crane parts. The guy is away looking it out for me in the next few days. It isn't the cross bolted engines. Is this the sort of thing you would advise? I heard the 3.9 often became porus is this correct?
Thanks Mark

[marko10010]

Just to be clear, this engine would be for the Dutton not the Scimitar BTW.

[kiwicar]

Hi
I thought porosity was and issue on the first "stiff block" 3.5s (the first post P6 3,5s) and only for a short time not heared of it on 3.9's but others will probably know.
Best regards
Mike

[DaveEFI]

Hi
I thought porosity was and issue on the first "stiff block" 3.5s (the first post P6 3,5s) and only for a short time not heared of it on 3.9's but others will probably know.
Best regards
Mike

Interesting - the post P6 3.5 must refer to the SD1, mainly? Never heard of one of those suffering from porosity.

[kiwicar]

Hi Dave
The context I remember it in was early stiff block 3.5 Range Rover after the P6 stocks finnished (forgotton when they went over but It was around '78, '79 ish) as I implied never thought it was much of an issue with the rover V8 and was related to production batch rather than an inherent design/ production problem.
Best regards
Mike

[ChrisJC]

My understanding is that the 'porosity' issue is the block cracking behind the liner on all the 3.7" bore blocks (i.e. 3.9 litres and upwards). I've never heard of it being a particular issue with the 3.5 litre block.

Chris.