Rover V8, SU v Edelbrock 500

[Happydaze]

The tube of you decided this might interest me. From a purely spectator perspective it did. Bit surprising really as many look to go down the 4 barrel route. Using a 500 though, which I thought were too big for an RV8, instead of the 390?


https://youtu.be/LN1XcBGKc8s?si=yokBqV9ROtwr6GAX

Chris



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[tom.marg]

As expected? 4 barrel will let it breath.
once tuned correctly I’d expect it so be much nicer than SU.
The 500 part would seem big, but technically it’s got room on the air side and tune the fuel side.

The 383 I used to race with had a 1050 on it. On the dyno the volumetrics were spot on, the motor pulled 950CFM. So 100Cfm ‘room’ if you like. Perfect it will never starv of air!

[kapri]

500cfm is measured differently to a 390 . One is 1" vacuum and other is 2" , apples vs oranges.


EDIT , I'm talking balls , they are not rated differently but apparently the 500 only flows 400 due to 'booster ring'?

[mygasser]

500cfm is measured differently to a 390 . One is 1" vacuum and other is 2" , apples vs oranges.

which is which kev? don't leave us hanging, lol.
neil.

[Happydaze]

500cfm is measured differently to a 390 . One is 1" vacuum and other is 2" , apples vs oranges.

I'll admit to being confused, which isn't uncommon!

I'd forgotten that the 390 I was referring to was a Holley 390cfm which seem to be marketed as ideal for 3500 RV8's. Unsure about the differing measuring sticks though.

Chris

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[Mick70RR]

Before 4 barrel carbs were available single and 2 barrel carbs were flowed at 3" of vacuum. When 4 barrel carbs came out the flow benches could not achieve 3" of vacuum because of the increase in flow through the carb, so 1.5" of vacuum was used as the standard.
As an example, the Mopar 6 pack carbs are rated at 1350 cfm, that's 3 x 2 barrel carbs, each rated at 450cfm and flowed at 3" of vacuum.
A Holley 4 barrel rated at 950cfm, flowed at 1.5" of vacuum flows the same amount of air as the Mopar 6 pack set up.
Two different carb setups with different flow ratings but they flow the same.

The Holley 390cfm and 500cfm carbs are both 4 barrels and so will have been flowed at 1.5" of vacuum.

[kapri]

Before 4 barrel carbs were available single and 2 barrel carbs were flowed at 3" of vacuum. When 4 barrel carbs came out the flow benches could not achieve 3" of vacuum because of the increase in flow through the carb, so 1.5" of vacuum was used as the standard.
As an example, the Mopar 6 pack carbs are rated at 1350 cfm, that's 3 x 2 barrel carbs, each rated at 450cfm and flowed at 3" of vacuum.
A Holley 4 barrel rated at 950cfm, flowed at 1.5" of vacuum flows the same amount of air as the Mopar 6 pack set up.
Two different carb setups with different flow ratings but they flow the same.

The Holley 390cfm and 500cfm carbs are both 4 barrels and so will have been flowed at 1.5" of vacuum.

Yeah ...THAT LOL . I was remembering electric fan cfm comparison at 1 and 2"

Again from memory 390 is actually a tad big for stock Rover 3.5 , 365 cfm requirement as stock ?

I'm SURE I read somewhere thta Edelbrock 500 was actually less flow that 390 RPI I think ?

EDIT , my meory is starting to fail I think. The truth is that apparently the 500 only flows 400 due to booster ring size ??

Anyway these figures would suggest otherwise ?

Edelbrock 500:
Primaries: 1-7/16"
Secondaries: 1-11/16"

Holley 390:
All: 1-7/16"

[Acker]

Interesting
I ran a [emoji6][emoji[emoji6][emoji6]][emoji[emoji6][emoji6]] double pumper on a race engine pushing [emoji[emoji6][emoji6]][emoji[emoji6][emoji6]]bhp
Never checked flow rates on it though.



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[mygasser]

Interesting
I ran a [emoji6][emoji[emoji6][emoji6]][emoji[emoji6][emoji6]] double pumper on a race engine pushing [emoji[emoji6][emoji6]][emoji[emoji6][emoji6]]bhp
Never checked flow rates on it though.



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sent from your iphone? seems you need an upgrade

[Willys coop v8]

I,ve got a edelbrock 500 on my rover sd1 3.9 and it's spot on . _smiley: