The V8 Owners Forum -

I've got a 4.6 Rover block & heads with all the ancillaries from my old 3.5 and it averages out at around 24mpg (the 3.5 averaged 22mpg). I've bought an Edelbrock 500 and Performer manifold to replace the twin 1¾" SU carbs and am thinking that unless the fuel consumption is a worse, the same cheapo ebay electric fuel pump I had on both engines will be ok.
Correct or am I missing something obvious?

As long as the pump can keep the carb full, it'll be fine.

I reckoned much the same but I think I might as well try to measure the flow rate just in case - apparently the Edelbrock can use more than the SU's under hard acceleration and if it turns out my pump can't keep up then I'll have an idea of what to look for flow wise.

10cc per hp per minute at wide open is an approximation I heard years ago.

Easy enough to calculate your approx hp and then time how long it takes your pump to flow a litre.

Then just some maths

Ian

Yes, I'd come across that approximation too, it gives 28 gallons per hour for 210hp.
To further muddy the waters, various pumps are using different calculations - the Facet blue top says 38 gph for up to 240hp (equivalent to 33gph for 210hp) and the Holley Mighty Mite says 25(UK) gallons per hour for up to 300 hp (equivalent to 18gph for 210hp) which is quite a range.
I've decided I'm going to measure my pump output and take it from there.

Facit are rated at UA gallons not U.K. gallons………so a lot less in litres