Electric fuel pump or mechanical

Doing my fuel system, 408, street car that will see track 3 times a year, 490hp, 950cfm carb, head work done at modern cylinder head. Engine has been on engine dyno only so far and broken in, so I have not driven it on street yet.

Here's what I have, new pick up in tank 1/2" IIRC, no return line in sending unit, 110g electric pump (holley blue design). I'm not married to the idea of this pump as I've not used it. But I'm reading and receiving mixed advice.

Is a return line a must for a street car?
Are there more cons with electric v mechanical?
Do I need return line with mechanical if I go that route?

From my experience w/ pump gas and street cars, I'd want an electric pump w/ a return line. The gas keeps getting worse and worse it seems and heat does bad things to it at the worst times when you're out trying to have fun in your hot rod.

I have a racepumps 2000 mechanical on my 572 with a return line. I have yet to try it out. Tim

That 110 Holley blue pump may be marginal for your current needs and possibly future needs
HP and going fast seems to stimulate a lot of us to seek more HP and quicker ET so do it once now on the bigger is better now than redoing it over later concept when you outgrow it

That 110 pump will be to small if you race
it... might just get a larger one now.. the
1/2" supply is plenty for you

I might go FI in 3-4 years so I will redo the entire fuel system then, for now I'm sticking with simplicity and going with a good basic pump (electric or mech) that will fill my needs. I should add it is a half filled block so the oil will run hotter and have been told that could make the mechanical fuel pump hotter as well, giving me more reason to run a return line.

I just added FI and have a return.. but I have been
running a return for years now.. you might want to
add that if you plan of FI in a couple of years.. just
dont hook it up if you dont want to

I would definetly run an electric pump with the pump gas of today. I just run the Holley black pump dead headed and it works fine. But its even better with a return line as I may add one some day. So far I have been good but you have to watch the real hot 95 degree and better high humidity days so the gas wont boil in the carb bowls and then it loads up and stalls running real rich. The electric pump will help fight vapor lock also. Ron

IMO this changes everything.

I would run an intank walbro style 340LPH pump and a regulator that will work at both carb and EFI pressures. A 340LPH pump will easily support 600 HP at EFI pressure, and will support 800+HP at carb pressure. The Aeromotive Phatom line is designed to go into a stock style tank, but a number of other companies have similar solutions. When you go to EFI, you will have to swap a spring in the regulator and hit the road...In tank pumps are quiet and stay cool. Do it once now and be set.

I always run a bypass return.

I must be missing something. The OP says he already has a holley 110 pump, Holley rates that pump @ 88GPH at 9 PSI. The op’s engine makes 500HP (corrected). When doing the MATH, that pump is more than enough (IMO). Let’s run the numbers. 500HP X .5 PPH / 6 (weight of fuel) = 41.66 GPH. Now having over 112% reserve seems like enough to me. And the OP will be running, for the most part, in air that is not as good as “corrected” air, so he will need even less fuel.

I am sorry but I went down this road once. I had a car making 675hp with a holley blue pump and was told “pump is too small, you NEED a bigger one”. I didn’t have a lot of money, so I skimped, saved and sat out some races until I could get one. After all that it didn’t make the car ANY faster, so now if the numbers don’t make sense, I don’t do it.

Joe

Thanks for input, I'm most concerned about safety and proper fuel intake for motor health, I'm not worried about what pump makes me go faster. The car is what it is, probably be a low 11 second maybe high 10 second car at best, and I'll live with that.

Where can I learn more about this pump or approach, I'm intrigued.

Here is some info on EFI style pumps:
http://realstreetperformance.com/Fuel-Pump-Comparison-Test.html

I am not trying to push Aeromotive, but they have some good info
https://www.aeromotiveinc.com/phantomdiagrams/

Regulator that accepts carb to EFI conversion
https://www.aeromotiveinc.com/product/x1-series-carb-bypass/

Phantom fuel pump kit: E-berg installed this on his EFI Road runner
https://www.aeromotiveinc.com/product/phantom-340-stealth-fuel-system/

Ricks tanks has a similar system:
http://rickstanks.com/products/in-tank-pump-kits/

Depending on the car, Tanks inc might have a fuel tank modified for an in-tank pump already, they sell fuel pump kits as well.
http://www.tanksinc.com/index.cfm/page/ptype=results/category_id=68/mode=cat/cat68.htm

Two great links for those tank options, thanks. I think Tanks Inc is a real good way to go, take old tank out, put that tank in, run lines and done.

Another option that doesn't require changing the gas tank:

http://www.robbmcperformance.com/products/powersurge.html

I run two pumps.. for cruising and most driving. I just use a hi volume carter mech pump.. but I have it plumbed so I can run an electric boost pump..at the track I run them both thru a pressure regulater to the carb.. Great to have a back up pump and after sitting a while I turn on the electric pump to fill the carb.. fires right up.. without cranking over a lot...