The V8 Owners Forum -

Think I am going to enquire about extrude honing. I think it's the only way to truly open up the Thor manifolds. Who do people recommend when it comes to top hat liners? I have seen that v8 developments do it. Think I'm looking at about a grand to do it but I'm not going this far with out doing it!

That's what i thought and why I mentioned about getting it extrude honed. That way the runners can be enlarged from the plenum all the way down the the intake port.

Not hell bent on figures I want the disco to have a decent improvement and keep up with modern equivalents.

Intake I'm thinking of just keeping the banana branch Thor manifold and the exhaust I'm going hedman 4 into 1 they have 1 1/2" primaries and a 2 1/2" collector. After them it will be sport cats and a free flow silencer all in 2 1/2"

Just been researching the 218 Kent and it says that the power band is from 1500-5000 as the disco is an auto and the
Stall point is 2000 rpm this should be good from pull away?

That's good to know. Is the reason I can't go too high on the compression with a high torque camshaft because there isn't much duration therefore the cylinder pressures will be a lot higher than they would be with a high duration cam? What sort of torque figure do you think I could achieve with that?

Interesting, so if I blueprint it to 10:1 that should make a difference. I then need to choose nice heads as I'm not up for porting them myself. I was looking at some v8developments stage 3 heads as I'm not sure stage 4 would benefit it any further. I've also been researching about merlins but seem ...

Ok as mine is petrol only I need to lower that a bit. I need bigger chambers then. Could I get earlier rover heads and skim them to get 10.5 to 1? Or I've heard good things about
Merlin heads and they come with a 32 cc chamber. Any one have any other ideas?

Something else I've been looking into is compression ratio. Using 4.0 piston on a 4.6 bottom end with normal 27 cc Land Rover heads the compression ratio comes out a 12.6 to 1. I think I'm doing some thing wrong as 12.6 is way to high for normal petrol. I know there meant to be 9.35 to 1 standard. O...

Oh and it seems all Land Rover made products have rough castings on them. Obviously it's the long runners in the manifold that give the torque. Would opening them out increase torque power? Or would it increase horsepower and not do anything for torque?

The cam isn't an expense I don't think as I have a piper torque max that I could swap out of my 4.0. It's only been in there around 800 miles. Don't mind spending some money on some nice heads of it will help. What sort of torque figures would this set up achieve?

I see what your saying. I just threw 300hp out there as it seems to be a good benchmark for a 4.6 n/a rover. What I was getting at was improving the breathing I know will improve more for horsepower than for torque. I just want to spend my money in the right places! Is there anything that can be don...

I would rather get it all laid out before i start so I can choose parts that all work together. How much torque could be obtained from a n/a 4.6? 320 ft lb 330?

Hi all, fairly new to v8's but now I am achieving one of my dreams by building one and dropping it into one of my favourite cars, a discovery 2. At the minute I have an all stock Bosch motronic 4.0 apart from a piper torque max cam. I'm looking to build a 4.6 cross bolted top hat block with 4.0 Pist...