Carb swapped ‘97 vortec - SUCCESS!!!

[BeXtreme]

Or just use a simple bypass style regulator instead of that double unit.

You can't do that with a pump designed to run at 4 bar. If using an EP381, you need the dual stage bypass like the one he bought. If he had put in a TBI pump when he cleaned the tank and replaced the pump... then he could have used the holley or similar bypass regulator to get the right PSI without killing the volume. It's really doing the same thing, but he just ended up spending double. The only reason to use the double regulator setup is so that you can keep the rest of the fuel system stock. The second he was going to need to replace the pump anyways, he got the opportunity to move to a lower PSI in-tank pump and save money on the regulator. At this point, he is already committed to needing to step down the high PSI because he already put a Vortec pump in it. The only benefit is that he won't have to replace the pump if he goes to a 5.3LS in the future. The downside is that if he does, the regulator he has won't be needed anymore.

 

[GreenMonkey]

If I'd known that I'd be going with a carb when I replaced my fuel pump, I would've gotten the TBI pump and saved some money. But you live and you learn. Does anyone know what would be a good psi to set the return line pressure too?

 

[BeXtreme]

If I'd known that I'd be going with a carb when I replaced my fuel pump, I would've gotten the TBI pump and saved some money. But you live and you learn. Does anyone know what would be a good psi to set the return line pressure too?

probably doesn't really matter. Pick a number and go with it. Does the included instructions not tell you what to set it to?

 

[GreenMonkey]

probably doesn't really matter. Pick a number and go with it. Does the included instructions not tell you what to set it to?

Haven't ordered it yet. I'm doing the conversion over the next month or two as I get some extra cash. Hope to start on the fuel system next weekend and I'll keep yall updated on how the regulator works. Thanks.

 

[Erik the Awful]

The pressure regulator itself is what develops the fuel pressure. Having a pump capable of 90 psi won't produce more pressure than a pump capable of only 20 psi, unless your volume is overpowering the spring. The part I posted is a bypass regulator, not a deadhead regulator. If you go to the Summit link I posted, in the Q&A the questions are asked.

I am switching from EFI to Carburetor. With this regulator having a return will it work with my current fuel pump that puts out 90PSI of fuel pressure. I would like to not have to buy another fuel pump.

The Holley Carburetor Bypass Style Fuel Pressure Regulators 12-881 Regulators will work with a 90 PSI fuel pump and will drop the pressure for use with a carburetor.

Will this work with an efi fuel pump?

Yes, as long as you use the return line you should be fine. Assuming your using a carburetor as you will be limited to the 5 - 9 PSI range of this reg.

 

[GreenMonkey]

So I’ve almost got the vortec to carb swap (1998 7.4 liter) wrapped up. I’m down to the wiring for the fuel pump. I’ve hooked the ignition wire(pink) from the coil to the battery terminal on the HEI and the tach signal wire from the coil(white) to the tach port on the HEI. However, the fuel pump won’t prime when the key is in the run position. What am I missing? My relay tested good and I never disconnected any of my grounds. The pump worked normally before the swap. I was under the assumption that the ECM primed the fuel pump and then the crankshaft position sensor provided the signal to operate the pump once the engine was running. If anyone has any words of wisdom, please help a guy out. Thanks in advance.

 

[Dk47]

So I’ve almost got the vortec to carb swap (1998 7.4 liter) wrapped up. I’m down to the wiring for the fuel pump. I’ve hooked the ignition wire(pink) from the coil to the battery terminal on the HEI and the tach signal wire from the coil(white) to the tach port on the HEI. However, the fuel pump won’t prime when the key is in the run position. What am I missing? My relay tested good and I never disconnected any of my grounds. The pump worked normally before the swap. I was under the assumption that the ECM primed the fuel pump and then the crankshaft position sensor provided the signal to operate the pump once the engine was running. If anyone has any words of wisdom, please help a guy out. Thanks in advance.

I thought I was having the same issue, wasn't getting any reading on my fuel pressure gauge. Found out that it don't run till it builds pressure, it just runs for a few seconds. I couldn't hear it until I got under the truck and put my ear against the tank.

 

[GreenMonkey]

I thought I was having the same issue, wasn't getting any reading on my fuel pressure gauge. Found out that it don't run till it builds pressure, it just runs for a few seconds. I couldn't hear it until I got under the truck and put my ear against the tank.

That’s exactly what happened to me. The floats were set so high from the factory, that it was over the sight glass and I thought no fuel was in the carb. Lol but it’s all good now. Starting up and idling smoothly. Ready to get this thing tuned and back on the street. Thanks for all the help.

 

[Jerryred94silvy]

So after seeing pictures of other people with a carb swap I’m wondering if something is off with my truck based on which way my distributor is facing. The truck runs alright (still learning carb tuning) and I have it set at 17 degrees initial advance without the vacuum advance hooked up. But my distributor faces a totally different direction than the others I’ve seen. What do you y’all think?

You must be registered for see images attach

 

[Erik the Awful]

On a small block Chevy you can clock the distributor housing any way you like and it will run, so long as the timing is correct.