Can I swap them?

I have a 1995 3.9EFI disco, I want to do some work on the engine but need the car daily. So I need to put another engine in, do the work on my own engine then swap back.
The reason is (1) because my compression is borderline low and (2) I want to get more power out off it by opening the ports up.
Now it seems that that the 3.5 is easier and a bit cheaper to get hold of. My question is if I get hold of a standard 3.5 carb engine can I swap all of EFI bits over or are the heads different too?

I am not a 100% but I think the efi unit should fit because you will remove the center valley plate and the efi should bolt straight to it but your efi is set up for the 3.9 and not 3.5 so it might not run right

Don't think for a second that a DIY job on the ports will make it more powerful. It might do exactly the opposite if it affects gas flow velocities harmfully.

CharlesY

as charles says simple port work on a v8 will do naff all! they need lots of money thrown at them to get any major gains, theyre far too crude.
3.5 will rum fine on your efi, know a few people who have done this with no probs at all.

if you want 150bhp more fit nitros oxide

Dont Efi heads have notches in ports for injectors?

I didn't think for one minute that porting them myself would do anything. I was going to look into having some professionals do that bit depending on price.
What it is I had to do the head-gasket before but did it in a rush. So it needs doing properly and while I have it all apart I want to overhaul it, as its on 110tho. And also I going to try to get more power out of it while I'm at it.
Any how I've manage to get hold of a 3.5 EFI for a foo-king steal so that can go in for now then I can get on with doing the other one.