Does the v8 conversion require any modification to the stock fuel lines? IF not, what line goes where from tank to carb?

Exactly what you do depends what engine was in the car to start. If it was a V6 and you hook 40+PSI fuel lines to a carb you'll have one hell of a mess.

also depends on what motor your putting in,carb or fuel injected. I changed all my fuel lines no big deal.

I'm in the process of installing SBC V8 4-barrel into 85 V6 F40. You need to put an adjustable regulator(Holley makes one)in the fuel lines to bring the fuel pressure down to about 6-8lbs. The larger of your fuel lines is your output from the pump(your filter canister is attached to this).The other is your return line. Sandy

quote Originally posted by cowans: I'm in the process of installing SBC V8 4-barrel into 85 V6 F40. You need to put an adjustable regulator(Holley makes one)in the fuel lines to bring the fuel pressure down to about 6-8lbs. The larger of your fuel lines is your output from the pump(your filter canister is attached to this).The other is your return line. Sandy

I am just trying to get educated as to how this would work. So the larger line is the one that goes into the carburator, say for example, a 600 cfm edelbrock. Is this the line that also gets a f/pressure regulator. Is 5psi good enough? The smaller line goes back into the fuel tank? So there are basically two lines to deal with. We are talking about a 2.5L engine here, so I understand that a v8 conversion uses the 4 cyl fuel pump also. ANY PICS out there of this set up?

I'm not familiar with the 4 cyl setup but basically a holley regulator has 3 orifices to it ...one imput (from your fuel pump/filter) and two outputs (1 to your return line to tank) and one to your carb! You can then add in place of your carb line a pressure gauge to adjust your pressure (turn screw on top of regulator) then re-attach your carb hose. Sandy

What he said.... The holley carb should tell you in the instructions what pressure it's wanting. If you don't have the book dig around on holley.com Diferant models have slightly diferant demands.

You have to use the bypass type regulator or the fuel pump likely won't last long. These let the "waste" pressure bleed rather than stall the pump, which would fry it. The regulator will explain how to hook it up. It's real straight forward.

You can't use the regulator with just an inlet and outlet. Those are for use with cam driven mechanical pumps only.

What a nice group of people you guys are!
One more question...what happens to all those little lines that go to and from the vapor canister and some vaccuum lines that were connected to the original 4 cyl engine?
I will look at summit for a holley fuel pressure regulator.

I've got a northstar V8 in my car. I'm not sure if it's the same in a carburated car but in mine I eliminated the vacuum lines that go to things that are no longer needed. This is where a good schematics comes in handy. For the canister...I can't remember what I did but it does need modifying. But this may all be irrelivent for a carburated car. Sorry.

Zorba, a few weeks ago you asked the Fiero forum on a Fuel Regulator hookup for a V8. I replied under "cowans". I was mistaken in my reply. If you are using a V6 fuel pump, you must obtain/install a 4cyl one.(v6= approx 50-60 lbs, 4cyl= approx 10lbs pressure). You can then use a low pressure regulator(Holley) to adjust pressure to the carb.(one inlet/one outlet regulator)....If you use one inlet/2 outlet regulator, block/plug 1 of the outlets. Also, plug your 5/16 fuel return line. I just found out I was wrong in my post to you....by experience. Good luck! Sandy

This is the one I have with a 4 cylinder fuel pump. The center bottom inlet says "IN"
and the other side outlets say "OUT"...should I still block one outlet or simply hook up the larger line to one side and the "return" line to the other side?
I suspect I have to have for the carb and the other one for the return line...does anyone one if these are factory pre-set at 8lbs? It's a holley fp.Brand new.

Zorba, I have the same regulator...After talking with V8Archie yesterday he suggested using a 4 cyl pump(installed last evening),...v6 pump puts out 50-60 lbs pressure/too much to regulate. Follow the larger line (3/8) past your filter, install output of your filter to your regulator(IN)side. From there, plug 1 of your outlets (3/8 pipe plug), connect 2nd outlet(regulator) to your carb,(install a pressure gauge between 2nd outlet and carb). The reason for the pressure gauge is to adjust pressure (at regulator adjustment screw)down to about 4-6lbs.(or so your carb gets enough fuel WITHOUT flooding). Finally, plug off your return line. So, in short, your are using a pump putting out approx 15 lbs,installing a "deadhead" regulator lowering the pressure down to 4-6 lbs to your carb. Sorry for the long-winded explanation. I intend on starting mine up tonight, will report tomorrow. thanks, Sandy

If I plug off the return line, does it mean that the line is no longer necessary with the v8 swap? You are suggesting to go from the filter to the regulator (IN) and then on line out to the carb, right? What is the function of the return line on a regular fiero set up? thanks!

And it runs!!! The V8 sounds pretty big with just 2 feet of flexpipe off each manifold...in the garage! Having a little trouble adjusting the regulator down to 5-6lbs but I think my pressure gauge is the culprit.(cheap) Zorba, In a fuel injection setup (which requires high constant high fuel pressure) you have a regulator that keeps constant pressure at about 40-45 lbs. The excess fuel is routed back to the tank via THE RETURN LINE. My research in finding a regulator that will step down fuel pressure from 50-60 lbs(V6 pump) to 5-6lbs(at carb) was that only 1 regulator(Mallory) could do this (although the Manufacturer would not recommend it) so the change was made to a 4cyl pump pushing 10-15 lbs fuel. If you use a return line with this setup, all the fuel will return to the tank....choosing the path of least resistance. Good Luck, Sandy

quote Originally posted by Zorba: ...does it mean that the line is no longer necessary with the v8 swap?

It means that the return line is no longer necessary with a carburated V-8 swap.

Sandy, you explained the situation perfectly, it's good to see the information getting relayed correctly.

Thanks

Archie

O.K. I just need to plug off one of the outlets (out) on the f.p.regulator, use the line in (IN) and hook it up to the carb. I am using the 4 cylinder fuel pump. I found a little fitting that makes provision for a small fuel pressure gauge. The fitting cost $7 at Checkers and the guage was about the same price. I will plug off the return line as you indicated. On a different note, can you guys clarify the wiring a bit more for a carb engine? Thanks.

Zorba, wiring a "CARBED V8" is faily straight foreward. From your engine harness, "pink" to your distributor "+", "white" to your distributor "-"(tach),use same wire "purple, I think" to starter solenoid. etc. V8ARCHIE's site is well worth reading, plenty of setup tips. Having said all that I'm not sure if a 4 cyl harness is similar color coded. If you're installing other gauges/Autometer/VDO/etc. there are archived messages on this, one from "Batboy" comes to mind. I'm installing 9 Autometer Phantom Gauges, have tested out my harness but not yet installed them, so, once they're setup correctly, I could list the wire/color....3-4 weeks! If you plan to use a new speedo be sure to keep the old one...from what I have been told you need to steal the "pulse" circuit board inside the original. You'll need this if you plan to use the original Cruise Control.
Archie,thanks for you kind comment,
Sandy