Fuel System for Carb 408 sbc

[Michael Bennett]

My car is an 80 Malibu with a 408 sbc ~475 hp. So far it's running 12.7 @ 107mph but laying down in 2nd gear. My current fuel setup is an Edelbrock Performer RPM mechanical pump hooked to the stock 3/8" fuel lines from the tank. Stock tank has been pulled and verified to be clean and good shape. Fuel is regulated to 5psi with no return to the 800cfm Edelbrock carb. The tank vents to the stock charcoal canister. I moved the fuel pressure regulator up to the cowl so I could read it when running down the road. Sure enough, it drops from 5psi down to 2.5psi under hard acceleration and higher rpms. My first choice would be to make it work with a mechanical pump. Maybe there's a better pump than I have? The other option I'd be interested in is possibly running a sending unit from a fuel injected Gbody and running an in-tank pump. I'm not really interested in running an external pump as they seem to fail and this car gets street driven a lot. Holley even has a nice set up that would drop right in my stock tank. What I'm wondering is if it would be okay to then regulate that 60psi pump down to 5 at the carb. Has anyone else done this type of thing? I've tried looking for a lower pressure in tank pump but not finding anything.

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[Ernest]

You seriously might think about putting a seperate return line back to the tank, and for that, you need a return/bypass style regulator as well.

What you are doing is dead heading the fuel to the carburator, that typically increases the temp of the fuel, and with todays ethenal blend, its boiling some of it into vapor providing less fuel and pressure.

An in tank fuel pump would be great(cooler running) with a return/bypass style regulator along with a return line to circulate the fuel to keep it running cooler, im not familiar about any regulator that will take 60psi and regulated it down to 5psi, even though i think 6psi max would be a better choice if running a holley.

Great track time with your '80 malibu and 406cid though.

EDIT: Example...

 

[78Delta88]

Get a TBI or TPI pump. 15 psi... Your issue is volume not pressure. The higher the pressure, the higher the $$$$. Plus now you will need bigger $$$ regulator, and if it fails you end up with this....

Holley 12-887 is the one you need. 5.5 to 9 psi

 

[Ernest]

If you want to upgrade to much better and do it on your own, lQQk no further...

 

[Clone TIE Pilot]

http://www.camarotech.com/engine-ZZ3.html

 

[78Delta88]

http://www.camarotech.com/engine-ZZ3.html

Looks like we'll laid out kit. TPI pump 14psi from Corvette. I was thinking the 803 Holley is non bypass return, I'll have to look that up. I went with the 887 but not hooked up or running yet in my project.

...looked it up; 12-803BP is the bypass return unit, approx. $60.00 more.

 

[bracketchev1221]

Fuel system doesn't lay down in second gear and fix itself in high gear.

 

[78Delta88]

...Has anyone else done this type of thing? I've tried looking for a lower pressure in tank pump but not finding anything.

Holley 12-129 is the turn key kit. 6 psi @ 255 LPH. Rated for 700 HP. At least that's what Holley is showing. I used calculator and got 252 LPH at 600 HP, so it is close.

With it only being 6 psi you could probably get away with the non return regulator 12-803 @ approx. $40.00. The 12-803BP return style is approx. $100.00.

For wire I would suggest 10G, hooked to the oil pressure switch. 14G might not be heavy enough.

 

[Michael Bennett]

You seriously might think about putting a seperate return line back to the tank, and for that, you need a return/bypass style regulator as well.

What you are doing is dead heading the fuel to the carburator, that typically increases the temp of the fuel, and with todays ethenal blend, its boiling some of it into vapor providing less fuel and pressure.

An in tank fuel pump would be great(cooler running) with a return/bypass style regulator along with a return line to circulate the fuel to keep it running cooler, im not familiar about any regulator that will take 60psi and regulated it down to 5psi, even though i think 6psi max would be a better choice if running a holley.

Great track time with your '80 malibu and 406cid though.

EDIT: Example...

Yes, I think a return line should be my next step before spending a bunch of cash. Looking for some instructions on how to add a return to my current sender. I think I can just drill a hole and run the tube through the sender down low enough that it doesn't splash and solder it in. I need to find some instructions on the soldering or brazing that I could do at home with a propane torch.

 

[Michael Bennett]

If you want to upgrade to much better and do it on your own, lQQk no further...

If I was going to do that, I'd just use the one they make for a GBody and not have to cut holes. It still doesn't solve the lower pressure pump for a carb issue. I might have to call them up.