[Chris65LeMans]

All,

After my 435 blew up earlier this year, I ended up going with a freshly-built 461 from Kauffman. It it done, broken in, dyno'd and on a truck for the journey out to me now. (FOUR months ahead of schedule!!)

It dyno'd at 498 hp and 581 lb of Tq, The carb will be a Prosystems 780 HP.

The engine will arrive with a Fuel pump block off plate installed. Jeff recommends either a Holley 110 GPH mechanical pump or a 180 gph electric pump.

What sort of opinions are out there on mechanical vs. electrical?

Thanks, Chris

[steve25]

With that many cid and HP, either pump is a moot point if your tank has the stock size pick and also if the rest of the fuel line is the stock inadequate size going to the front of the car!

[JSPONT]

I like overkill. I love Aeromotive stuff. Return lines to me, are a must. I also use a Ford solenoid and a switch. It's nice to kill the pumper and run the bowls out of the crap ethanol over the winter.

[78w72]

depends on what your plans for the car are, if drag racing or hard auto x'ing then electric is best, in tank electric is even better.

if only light racing/mostly street then you can get by with a mechanical. i would suggest robbmc over a holley any day though, or even the edelbrock 1713 over a holley. i havent tested a holley but did use the edelbrock on my 467 stroker that made 520hp on the dyno with no tuning at all, just a cliff built q-jet & sun tuned GM HEI. in a 72 firebird with stiff suspension the E-pump went 12.2 but had pretty bad starvation issues, edelbrock says it supports "up to" 600 hp but that is obviously standing still on a dyno. the robbmc 1100 i have now has ran a best of a high 11.2 but still has some occasional cut out issues but is dialed all the way down to ~7-8psi. both pumps had a 1/2" pickup & full 1/2" lines from tank to pump & pump to carb.

so really comes down to the cars purpose, if i had it to do over again from the start i would have went with a in tank set up & still considering that if i cant get the mech pump to work right.

[Tom Vaught]

Originally Posted by Chris65LeMans

All,

After my 435 blew up earlier this year, I ended up going with a freshly-built 461 from Kauffman. It it done, broken in, dyno'd and on a truck for the journey out to me now. (FOUR months ahead of schedule!!)

It dyno'd at 498 hp and 581 lb of Tq, The carb will be a Prosystems 780 HP.

The engine will arrive with a Fuel pump block off plate installed. Jeff recommends either a Holley 110 GPH mechanical pump or a 180 gph electric pump.

What sort of opinions are out there on mechanical vs. electrical?

Thanks, Chris

Could you explain why you need such a large electric fuel pump on your 500 horsepower engine?

For example a 200 GPH electric fuel pump from Holley (a Dominator Electric Fuel pump) will support 2100 carb horsepower.

https://www.holley.com/products/fuel.../parts/12-1800

That is over 4 times the HP of your Dynoed engine.

Please share why you need such a large (180 GPH) electric fuel pump.

Tom V.

The old Holley Blue Pumps were rated 110 gallon/Hr but that was FREE FLOW, (NO RESTRICTION IN THE SYSTEM) AND WAS
grossly overrated. The New Electric EFI type Pumps have far more fuel delivery capability.

[78w72]

Originally Posted by Tom Vaught

Could you explain why you need such a large electric fuel pump on your 500
horsepower engine?

Please share why you need such a large (180 GPH) electric fuel pump.

Tom V.

kauffman recommended that pump, hes just stating what they said.

[wbnapier]

455/469 engine. I have a 5/16" feed line and regulate the fuel pressure at 3psi for a tri-power. I can WOT all 4 gears and never run out of fuel. Mechanical pump.

[Tom Vaught]

Originally Posted by wbnapier

455/469 engine. I have a 5/16" feed line and regulate the fuel pressure at 3psi for a tri-power. I can WOT all 4 gears and never run out of fuel. Mechanical pump.

TRI-POWER = 3 large fuel bowls. I could post the same thing using my 3 Holley
(500 cfm) each Carbs I have mounted on an aluminum Tri-Power Intake.
That is 500 cfm (2-Barrel rated cfm) or 370 cfm each when rated like a 4 bbl.
So a 1000 cfm induction system.

Tom V.

[Mike S]

I have been using a Carter mechanical pump for 20+ years. Trying to remember, I think it was 120 or 130 gph. Using the stock fuel lines also. I am guessing 500 hp it has been ran off and on at the track for 20 years. It will run 11.80/113 at 3900lbs.
Don't over think it. Mechanical is all we had in the day.

[JSPONT]

Yup Tom you just proved my point. You should have all them folks add you to their signature. Steve Morris would be nothing with out you I am sure. Nut hugger is a term for people who hang on other ones accomplishments. You would be better off listing your Ford accomplishments. Even though I do know some of them from past posts. Marty could have never gone that fast with out you I am sure. TBH big money, testing and time is what it takes. I will agree Marty was way ahead of his time. Pretty sure you will still respond even though you said you have no time. Looking forward to it. I will leave you with this, no one wants anyone's resume on every post, guy has a street car looking for a decent fuel system. I will not respond to you in this thread anymore and crap up the guys post. Cheers

[Tom Vaught]

Originally Posted by JSPONT

You would be better off listing your Ford accomplishments. Even though I do know some of them from past posts.

Then nothing more needs to be said. Is There?

For a Street Car a 7/16" Relief Ball Regulator from Holley works great.

https://www.jegs.com/i/Holley/510/12...RoCL7sQAvD_BwE

Same deal with the good 4070 Carter Electric Fuel Pump

https://shopfasttrack.com/products/c...hoCUnsQAvD_BwE

Tom V.

[turbo69bird]

Originally Posted by wbnapier

455/469 engine. I have a 5/16" feed line and regulate the fuel pressure at 3psi for a tri-power. I can WOT all 4 gears and never run out of fuel. Mechanical pump.

That is a feat let me tell you, I agree most cars are over pumped and that’s cheap insurance. And sometimes a smaller line is better especially on launch but man 5/16 is pretty small. Wonder how close to the ragged edge this thing is and if it’s getting lean .

Lean is mean, cars probably fast as hell because of it. (Obviously it’s not nosing over) Would love to see a wide band O2 in this car.

Ever check your plugs ? Wide open run , chop it and pull the plugs? If it’s truly making it and staying rich enough, with That set up that impressive.

[wbnapier]

Originally Posted by turbo69bird

That is a feat let me tell you, I agree most cars are over pumped and that’s cheap insurance. And sometimes a smaller line is better especially on launch but man 5/16 is pretty small. Wonder how close to the ragged edge this thing is and if it’s getting lean .

Lean is mean, cars probably fast as hell because of it. (Obviously it’s not nosing over) Would love to see a wide band O2 in this car.

Ever check your plugs ? Wide open run , chop it and pull the plugs? If it’s truly making it and staying rich enough, with That set up that impressive.

I have a '65 GTO, so the tank to pump is 5/16", then it's 3/8" from pump to fuel block on the tri-power. The tri-power has mostly 5/16" lines going into the fuel inlets. The fuel inlets have a pretty small diameter inlet.

No return line.

For those that like to get into the weeds, you could do a hydraulic analysis on your fuel system and you'd be surprised at the results.

I have a wide band O2!. I just reduced the size of my outboard jets from 74 to 72 as the AFR was 12.0 at WOT. With 72s, I am 12.25ish. I am now 72-64-72.

When I changed the jets, on start up, my rear carb float stuck and fuel poured out of the bowl, then out the top. I was shocked how much fuel flows to those at 3psi. I'm actually at 3.2psi. The pump is the ROBMC one if it matters too much with a 5/16" feed.

As for plugs, I don't like how they look, but I'm not an expert, and I have the 02 sensor that tells me I'm good.. Zero knock with 91. Attached are plug photos.

Really sorry for hi-jacking this thread.

[Formulajones]

My take on the question, if you're considering going electric, put it in the tank, period! There is a reason OEM's put pumps in the tanks. Cooler operation, quieter operation, with the right pump you never have to worry about fuel starvation and you get OEM reliability, 99% of the time if done correctly you shouldn't have to worry about it for many years.

I don't have a problem with mechanical pumps either. Our daily drivers are mechanical pumps. I've been able to make stock AC mechanical pumps go mid 12's at the track without issue and they daily drive just fine. Seems once I push over 400hp they become a fuel delivery problem though. Higher output mechanicals can solve that to a degree but they really need big pickup and feed lines if you expect them to keep up on anything around 500hp or more.

For the OP's power level I'd probably want an electric in the tank because I know I'd be taking the car to the track a couple times a year for some fun, and spirited driving on the street occasionally.
For his purposes a really good mechanical would be okay. A RobbMC would be my choice. Even if it's just a cruiser you know there is going to be some spirited driving and I'd want to make sure delivery isn't an issue.

If you put a mechanical pump on the car that needs supplemented with an electric, then it's time to step up to a big boy pump. Either a bigger mechanical or just put the electric pump in the tank and be done with it.

The real reason people don't do it is because of cost and the extra work involved. Hey, it's a classic car, they cost money and you have to work on them once in a while, that's classic car life. It's supposed to be fun

[turbo69bird]

Originally Posted by wbnapier

I have a '65 GTO, so the tank to pump is 5/16", then it's 3/8" from pump to fuel block on the tri-power. The tri-power has mostly 5/16" lines going into the fuel inlets. The fuel inlets have a pretty small diameter inlet.

No return line.

For those that like to get into the weeds, you could do a hydraulic analysis on your fuel system and you'd be surprised at the results.

I have a wide band O2!. I just reduced the size of my outboard jets from 74 to 72 as the AFR was 12.0 at WOT. With 72s, I am 12.25ish. I am now 72-64-72.

When I changed the jets, on start up, my rear carb float stuck and fuel poured out of the bowl, then out the top. I was shocked how much fuel flows to those at 3psi. I'm actually at 3.2psi. The pump is the ROBMC one if it matters too much with a 5/16" feed.

As for plugs, I don't like how they look, but I'm not an expert, and I have the 02 sensor that tells me I'm good.. Zero knock with 91. Attached are plug photos.

Really sorry for hi-jacking this thread.

The O2 sensor isn’t gonna lie, well done!!



As for the OP I’d say you engine builder is just being safe which makes sense. Could you get away with less probably, but for an engine builder you always want to see a car a little on the safe side . No one wants guys blowing up engines w your name on it

I do a lot of turbo set ups and my stuff lives when so many other don’t. It’s simple. I over fuel and under time it and it’s fat lazy and happy.

The okd stock eliminator guys would purposely run and air leak usually carb gasket loose jet the hell out of it and make it run like a higher CFM carb. Usually lose the front so when at full throttle it would tip the carb back. Anyway this taught me that keeping car fat was worth it’s weight in gold for survival . Because of you get a leak or any other issue being a little on the fat side is a good place to be
More fuel
Pump than you need likely is good cushion to.

[Tom Vaught]

OK Thanks. I would talk to a few Electric Fuel Pump suppliers like Aeromotive and
the Holley Guys for your street Carburetor application. Would not like to see a carb fire
from the needles and seats being over-powered.

If you stay with that pump get a very good fuel pressure regulator.

Tom V.

[Chris65LeMans]

Car will be street driven only. Good points on the fuel lines - we’ll have to look at them.

[78w72]

Originally Posted by Chris65LeMans

Car will be street driven only. Good points on the fuel lines - we’ll have to look at them.

for street use only, a good mechanical will be fine, nice simple dead head set up & the E-pump & robbmc can be ran without a regulator on carbs that can handle ~6-7psi. the 1100 will dial down to ~7psi & the 550 is preset at 6.5-7psi.

the only real benefit of electric for a street car is easier starting after sitting for a week or so, but even with a mech pump i just need to crank it over for 3-5 seconds 1-2 times to fill the little q-jet bowl & it fires right up. probably wont be an issue with a holley though & less chance of starvation with the 2 big fuel bowls.

[tom s]

Carter street pump is all you need.Tom

[78w72]

Originally Posted by tom s

Carter street pump is all you need.Tom

im sure the carter is a good pump, but when i was researching mechanical pumps what i didnt like about the carter is its states "stock flow" on summit & doesnt say a real GPH, do you know what its rated at? id imagine its listed on carters website but i didnt get that far when using summit to compare pumps & picked the edelbrock that states GPH of 110 & a claimed HP rating of up to 600hp. both robbmc pumps beat that number by a pretty big margin.

https://www.summitracing.com/parts/c...SABEgKxVPD_BwE

& after looking at robbmc site they compare the 550 to the carter, looks like carter is about the same 110gph as edelbrock, but the 550 beats it pretty bad in free flow & even worse at 4.5psi.

https://www.robbmcperformance.com/pr...ontiac550.html