The V8 Owners Forum -

Has anyone fitted a 4.6 into their 110? I have a 4.6 I was going to rebuild and fit in place of my 3.9 but was concerned that it may be too expensive to run. The 3.9 with disco transfer and ZF gives me around18mpg and although could be more powerfull isnt too bad, just lacks when towing. I do now have a 1.41 transfer I could fit which would help for towing, not sure how that would go. Its pretty quiet on the road now, and drives well but as always looking for that little bit more

I'd not have thought it would make much difference to the MPG - unless you use all the extra performance all the time.

I would stick with the 3.9 and give it stage 1 heads, a new standard cam and a set of tubular headers, add an aftermarket ECU and you will have better performance, better fuel economy and change in your pocket.
Best regards
Mike

I'd fit the 4.6 - the extra torque will be better with the auto.

I think fuel consumption will go down because you'll use the extra power. But it will be a nicer drive.

Chris.

kiwicar wrote:I would stick with the 3.9 and give it stage 1 heads, a new standard cam and a set of tubular headers, add an aftermarket ECU and you will have better performance, better fuel economy and change in your pocket.
Best regards
Mike

3.9 was rebuilt a couple of years ago, new standard cam, has 3.9 disco manifolds with a larger bore right thru to tailpipe, and new carbs. Has 10 bolt heads, interim motor. Im not in a rush but just wondered if anyone else had any figures of what I might expect. If its too bad I guess I could always swap the 3.9 back in again. Will probably not be a daily driver anyway, probably keep a RR for that.

doubt you'd see any difference TBH unless you are heavier on your right foot

My brother has a 4.6 in his stage 1.Fuel consumption no worse than the 3.5 he had in before.Much nicer to drive.