just a quick question for someone that might know, can you bore a 4.0l and use 4.6l pistons? If so, can you use the 4.0l rods and crank with the 4.6l pistons??? THANKS!!!

 

No need to bore it, the 4.6 is a 4.0 with a longer throw. (or is it shorter? I forget)
All you need to do is replace your 4.0 insides with those of a 4.6, so different crank, connecting rods, cam and ECU, without the 4.6 ECU you wont net anything other than money lost.

 

Stroke it, add a 4.6 cam, maybe clean up the heads a little and you are set.

 

is the rover 4.6L the same 4.6L ford uses in half it's vehicles or is that just a coincidence?

ok, nevermind I see now that they first used their 4.6L back in '96 when they were owned by BMW.

 

The Rover 3.9, 4.0 and 4.6 are all the same exact engine, just different stroke.
I think but do not know for sure that the 4.2 is also the same engine.

 

The RRC 4.2 looks almost identical to the early D1 3.9, so I'm pretty sure it's the same.

 

Can you do the same with the 3.9L with a mechanical distributor? Do you really need the ECU? Mines a 5spd so don't think I'll be able to find a 4.6ECU that will work.

 

On a 3.9, consider have the heads enlarged, a cam, headers, possibly larger injectors and you'll make even more power.

 

Yeah I'd seen that the 4.6 RR P38 comes with factory headers? I was wondering if I could make those fit on to my old D1? Guess I'll have to keep an eye out for a cheap 4.6 P38 parts vehicle so I can experiment.


P38 headers:
http://cgi.ebay.com/ebaymotors/ws/eB...m=150334266698