How much fuel does a carb flow?

[green69rt]

I would guess that the first answer I'm going to get is "it depends".

The reason I am asking is I'm looking around for engine parts and started to look at mechanical fuel pumps.   There are stock ones that seem to flow around 20-30 GPH and then the next size is 120 GPH.  That's quite a difference and the price shows the difference.  Right now I'm guessing that my car will be running about 500 HP max on a 500 cu in engine, 750 CFM carb.  On my old 440 RT I ran a stock mechanical pump and never ran out of gas, even on long runs with my Holley 800 CFM carb and peddle to the metal.  So any recommendatons?

[c00nhunterjoe]

The stock mechanical pump cannot keep up with a performance build in almost all cases. If you want to stay mechanical, the.... carter (pn slips me right now) that i beleive mancini racing sells, will fulfill 90% of the street builds needs given you have 3/8 line. Gph is like cfm... people live by the numbers but most dont know what they mean or why and when they are important.

[green69rt]

The stock mechanical pump cannot keep up with a performance build in almost all cases. If you want to stay mechanical, the.... carter (pn slips me right now) that i beleive mancini racing sells, will fulfill 90% of the street builds needs given you have 3/8 line. Gph is like cfm... people live by the numbers but most dont know what they mean or why and when they are important.

I do have a 3/8" supply and a 1/4" return (I plan on the vapor seperator) and I did see a Carter pump on Mancini, still 120 GPH.

https://www.manciniracing.com/cabheen5psis.html

So rather than cheap out with a stock type pump, just go with the Carter and be done with it?

[Challenger340]

The stock mechanical pump cannot keep up with a performance build in almost all cases. If you want to stay mechanical, the.... carter (pn slips me right now) that i beleive mancini racing sells, will fulfill 90% of the street builds needs given you have 3/8 line. Gph is like cfm... people live by the numbers but most dont know what they mean or why and when they are important.

I do have a 3/8" supply and a 1/4" return (I plan on the vapor seperator) and I did see a Carter pump on Mancini, still 120 GPH.

https://www.manciniracing.com/cabheen5psis.html

So rather than cheap out with a stock type pump, just go with the Carter and be done with it?

YEP !

[c00nhunterjoe]

And yup

[green69rt]

OK, you guys convinced me.    (That's me on the right.)

[XH29N0G]

What do you make of this?  https://www.onallcylinders.com/2013/05/16/what-size-fuel-pump-do-i-need-your-top-tech-questions-answered/ 

[green69rt]

What do you make of this?  https://www.onallcylinders.com/2013/05/16/what-size-fuel-pump-do-i-need-your-top-tech-questions-answered/ 

Looking at all the equations, it looks like I need about 50 GPH at full throttle, so something more than stock.  Still going with the Carter.

[c00nhunterjoe]

OK, you guys convinced me.    (That's me on the right.)

No head smacks required. Legitimate question asked and answered. Nothing wrong with doing your homework

[green69rt]

OK, you guys convinced me.    (That's me on the right.)

No head smacks required. Legitimate question asked and answered. Nothing wrong with doing your homework

Lot's of questions, luckily I have CDR nearby to help.