Have seen people with the boa and bob engine in sierra's and believe doing this as a rear wheel drive conversion to an EsCos would be fairly easy, but wondering how much more effort it would be to make it 4wd and the best route to take.

I'm also not opening up the V6 vs YB arguement, not interested in that just the original question and what would be involved beyond the obvious.

Cheers

 

i fitted a bob 4wd in my escort cosworth track car after i popped the yb engine!
Straight forward but had to get the downpipes made!

 

it's actually easier to fit them using the 4wd setup than the 2wd stuff as you need to bugger about with gearboxes whereas fitting them to a 4wd set up all you need to do is source a 2.9 xr4x4 sierra and transfer the bits over

if you want to go the 2wd route you need to source a 2wd dohc 2.0 sierra as well to get the back of the gearbox off of and the cradle etc

 

so as far as differences and bits needed, would it be possible to use cosworth 4x4 running gear exclusively including hubs etc, or do you need to use xr4x4 running gear? I'm assuming the cosworth sump is different to the v6 sump so is the front diff different also? what would be the best choice.

 

You need the v6 sump and gearbox for starters, plus the flywheel and engine mounts and mounting arms to swap over plus the front suspension (as the v6 weighs more) at the very least

The rest of the stuff you can mix and match