The V8 Owners Forum -

Just a quickie guys. Been offered a set of 40dcnf quad carbs, my engine is staying at 3528cc (Rover), but will have a very wild cam, big valve heads and some decent compression.

Will 40's be enough or shall I wait to see if some 45's come along.

Look forward to your responses, Lee.

Hi,
They are very suitable for a rover 3.5, bit small for a 3.9, they should work very well with the right cam, heads and inlet. Getting a suitable inlet manifold may be a bit tricky unless you are planning on having one made to spec. Of the webber carbs the DCNFs flow very well for the size of venturi (less cluttered design than the DCOE) and should give very good throttle responce and good power, but that is providing the rest of the spec is properly matched to make use of them.
Best regards
Mike

kiwicar wrote:Hi,
They are very suitable for a rover 3.5, bit small for a 3.9, they should work very well with the right cam, heads and inlet. Getting a suitable inlet manifold may be a bit tricky unless you are planning on having one made to spec. Of the webber carbs the DCNFs flow very well for the size of venturi (less cluttered design than the DCOE) and should give very good throttle responce and good power, but that is providing the rest of the spec is properly matched to make use of them.
Best regards
Mike

Thanks Mike, they do have a manifold, but it looks awfully home-made, so unsure of how well it is made.

I will see how cheap I can get them, then it won't be too much of an issue if they turn out not to be suitable.

Thanks again, Lee.

What are you revving to with the wild cam

From the weber manual - a 425CC pot at 6000rpm will need a 34mm choke which is the max for a 40mm - about right for a stage 1 motor.

For 7000 RPM = 38mm Venturi

My advice - Hold out for 45's - 40's are too small.

Andrew

can you put a picture on them up.


dcnf carbs will need to be infront of each other like soldiers.

like in this complex diagram.

<------ front of engine
8 8 8 8