> SU Carburettors have become very expensive new if indeed you can stil get them, and used ones in good order are becoming almost mythical,
Twin SU's can be used even up to 4.6 litre (4WD) application non-race/high- torque) but it is advisable to at least recondition them, and essential to re-jet them accordingly (even for a camshaft or similar improvement). This should best be considered as something that will 'work' [hopefully] until the Weber or Optimized Injection can be purchased.

Fuel Injection, in the above information, I offer a comparison between optimized and 'non-standard' injection. The reason is that most second-hand injection systems (after you have shelled out good money) are far from adequate (you can find more info on this FAQ site) and, if you don't already have it fitted, you will find it's far more expensive and more complicated to fit than most would have you believe (especially the seller). So, again, in most case I would recommend the Weber.

Weber 500, so often the best choice

The Holley has never been too good at being flexible when it comes to the Rover V8 engine and it was always a little too small for large, powerful V8's, and a little too big for smaller, more economically minded V8s. Then came the Weber Edelbrock carb system, and a 200-500 cfm variable has turned out to be a real winner for part throttle economy with Throttle response, Torque and BHP gains throughout the entire rev range, and with very smooth and enormous top-end potential on any engine up to 5.2 Litre.

This is an area with little information available, but in our case the truth is out there working, Among many other successful applications and many hundreds of units sold, we sponsor a 4.6 Rally 4WD in Dubia that has been using the Weber 500 with Edelbrock High Rise intake for over 2 years. It provides huge torque for race-spec 4WD off-roading, and has superb manners when on road in between rally sections. This vehicle is expected to leap from 60 ft. Sand dunes and take sliding corners at flat-out speeds. (4.6 RPi Race Spec Engine) and the results with the Weber are superb: no flat spots, no stalling engine, no loss of power and with unrivalled throttle response.

A reason for this may be the location of the Float Bowls. On the Holley (renowned for problems off-road) the float bowls are mounted front and rear, this means that when on steeper inclines the fuel transfer hole becomes flooded or starved and would normally lead to engine stalling, but on the Weber the float bowls are mounted on the sides and the fuel transfer is in the centre, so no adverse affects are experienced on steep inclines. This makes good sense as all off-road vehicles can stand steeper climbs and descents (rather than traversing around steep inclines) before becoming overbalanced.

I have also used my Own 4.6 Range Rover with the Weber 500 / Edelbrock for over 9000miles, travelling all over and subjecting it to all work loads, including Drag Racing, Off Roading, Being a Farm Tractor (see picture gallery), Swimming, Comp. Safari'ing, oh and normal road use too and, depending on my driving style, I always got ...

Huge Torque for pulling power and steep inclines

Excellent Economy (up to 23mpg (4.6 Stage 3 Engine) on part throttle and cruise driving.

Superb performance, (0-60 in 7.8 Seconds) and 100 up in less than 25 seconds (only when economy did not matter).

Simple to install, set up & maintain (we now have an LPG converter available for the Weber 500).

Although this would normally be a problem with SU, Stromberg or Holley, Carb choices. The Weber 500 system, is so very simple to jet that we can even do it for you prior to dispatch

We have all jet & needle sizes and data for almost all Rover V8 engine specifications that we can normally get things spot on first time. If not we will send replacement needles, jets to fit yourself, and even if you have changed your engine spec, you only pay once.

Re-use, of your original thermostat housing, does not allow the water outlet from the rear of the water pump to pass coolant through the intake manifold (on some original Rover intakes it appears to go underneath, but it actually opens up into the manifold in the center, (underside) ).

Rover intakes have always and necessarily had this type of coolant bypass allowing for a slight volume of coolant to continuously circulate even when the thermostat is shut. without this required feature, incomplete Weber installations kits will lead to problems with coolant circulation and higher engine running temperatures,.

Ever wondered, why? Some Carb Kits cost more than others ?.

Here, you can see the the two threaded holes for the thermostat housing, plus the additional water intake port, @ the '7 o'clock' position, There are two suitable type's of thermostat housing available in our kit, 'read on'.	This type 'Shown', is generally correct for most 2-wd application's.. ie, P5, P6, SDi, MG, (inc MG'RV8), TR8, Morgan plus 8 & most 2-wd. Kit Cars.. Notice the additional water pipe corresponding to the manifolds coolant intake port.
The four wheel drive version of our thermostat housing range, is one that we have manufactured in-house & is unique for Land Rover and Range Rover applications, Note the angle of the top-water-hose is changed in direction plus the additional inclusion of a water temp sender, boss (there if you need it)...	Because of slight imperfections/variations in the castings of both intake manifold and the thermostat 4wd housing , some metal reduction may be require in the area of the housing shown, here Dont worry, It wont invalidate your warranty !!!

Advice applies to Holley, Webber, SU & Zenith Stromberg Carburettors, and is critical for good engine torque economy, and efficiency (regardless of how much you spent on other expensive bits).

The CO & HC Emission test/set-up that you may have had carried out for your MOT or Service, can be quite misleading. The reason for this is that they are generally only tested at idle, or low RPM. When tested at idle this has very little reference to your actual fuel mixture when driving, as the carburettor will now be reliant on its needle and valve profile to correctly supply the most efficient fuel/air ratio at all engine speeds and load conditions. When tested at low RPM this is only relevant to low-speed, low-engine load conditions and again cannot be of great importance.

One way of telling how the mixtures are, without putting it on a rolling road is to introduce a little choke at varying engine loads, and see how it responds. To See: 1, If the performance stays the same 2, it it floods/loses power. 3, of if a power response is apparent. This should indicate any weak mixture areas quite well, and a richer needle should be selected. If giving choke makes no difference then you could go slightly weaker on the needles to optimize, but only one stage would be advisable. If giving choke worsens things, then this is a sure indicator of an already rich mixture that should be dealt with. Also be aware you may get different results at different engine rpm's load and choke settings, all data is quite relevant to getting a good idea of what's happening (who needs expensive equipment?).

If you find that you or your engineer are having some problem getting both low HC's and Low CO's this is likely to be a sign of worn cam lobe[s] (normally affecting only one or two cylinders so enriching or weakening 4/8 Cyl's at once would cause the 7/8 good cylinders to run weak/rich (depending on which way you adjusted to compensate)), or a problem with you ignition Spark Intensity or Timing (including correct advance systems) (see relevant section).

The best engines are always those that are set up properly with components that are well matched and well suited to all other aspects of the engine in which they are required to work, and, very importantly, your actual driving requirements. Even a Ferrari or Lamborghini engine would be slow with an inappropriate or badly set up carb/injection system.

With my LHD Range Rover, the link for throttle does not install correctly - it seems like the throttle pedal has a shorter movement than the cable / carburetor fittings are supposed to have. The result of this problem is that when putting the throttle pedal to the floor, it is still missing about 30% of maximum travel on the carburetor (this means the two extra ports on the carb does not open...).
Because many vehicle use different throttle pedal leverage ratios, this can be a problem, but easy to rectify. If you drill further up the carb linkage and relocate the throttle cable connection. You can easily correct the ration between pedal travel and carb throttle opening ( you may need to bend/re-shape the linkage to accommodate the changed fixing.

		You can see from these two close up pictures, that when using the lower JWR Offenhauser Manifold it is required to bend the throttle linkage as shown and to affix the throttle return spring to the rocker cover fixing bolt., as shown from both these close up views.

Serp. type hose is different. as you can see from this layout.	Serp type water pump is very different to all pre-1996 engines.

This system is plug and play and I am happy it went well.

Hi Chris You were spot on. It was the ignition timing.

Weber & the Rover P6 Model (Option 1) It has come to our attention, that the Rover P6 at least has a mechanical throttle linkage. The Auto kick down linkage is easily adapted to do the job of the throttle cable. This can be done by making a linkage to go from the bell crank (kick down linkage) shown here down to the throttle bar that crosses the bulkhead.	Adapted Auto Linkage
Using the normal throttle cable.	Option 2 Alternatively you can use the throttle cable supplied with the kit. It is fitted to the Weber carb. as normal and then goes down the back of the engine towards the bulkhead. The cable should then attach to the lever on the end of the throttle rod that crosses the bulkhead.

From the Front With the rule placed at the base of the Valley Gasket - Allow 21.5cm	From the rear With the rule placed at the base of the Valley Gasket - Allow 25cm
From the side With the rule placed on the Rocker Cover - Allow 12cm With all measurements we are allowing for 0.5cm extra bonnet clearance for the centre wing nut. The manifold used was the Dual plane Offenhauser (the lowest possible). If you already have a Holley carb fitted the Weber 500 will be slightly lower on the same Manifold and is a simple conversion with no intake mods or upgrades required. Customer Frequent Questions Chris. Not only an excellent web site, but an excellent response to my questions. Your company really values customer service and it shows. Based on the information you have provided, the Weber conversion is the best option. A couple of questions. 1.What's the difference between the Edelbrock and Offenhauser manifolds, is it a matter of what Engine type I have or do they offer different performance options? The main difference is bonnet clearance, but the higher rise Edelbrock as they tell me should have a few more BHP on the top, yet I have never noticed any difference. 2.You mention jetting the carb for individual needs at an additional cost. Is this based on the engine type or can this be done when I tune the car after installation We can supply a jetting/metering rod kit but as we have done so many we can get close to what most need and charge a small fee to swap out the jets with what we consider you would need. If you find them too rich or weak we can exchange for another set up by post (not often needed). 3. I have been looking for electronic ignition, is the Mallory Dual Point `electronic` (please excuse my ignorance)? It seems you are suggesting doing the Carbie upgrade plus the distributor. That makes sense to me. For sure because one will only ever be as good as the other. You can do one at a time but you'll never know what it's capable of unless you improve all possible weaknesses and spark output, for the V8 is an issue of aged stock systems for sure. 4. Do I need to upgrade the fuel pump for the Weber? Not if you have a good stock or after market one already. You will know if it can't cope as you run out of horses at the top end and if adjusting float height does not cure it then it's a sign of a weak pump for sure. 5. What is the cost of the Mallory Dual Port and do I need to upgrade my coil? We supply coil and Ballast resistor with it, and for up to date prices please contact us Customer comments section now moved, 'Click here' Even more customer feed-back, on what makes it worthwhile. This FAQ Q/A Section is solely for information exchange only, and RPi or its contributors accept no lability for any issues arising from following up on our printed advice, or subsequent cost that may arise from the same. For our part we do our best to check all information provided and printed is correct to the best of our knowledge. And as V8 specialists for 15 years we don't get it wrong often. .