Can I run two walbro pumps on the stock wiring. I'm planning on running two pumps at once all the time. Is this to much for the stock wiring.

thanks in advance

 

Don't do it.

Rich

 

NO, stock wiring is not good for two 255 LPH pumps (assuming that's what you mean by a "walbro").... the stock wiring is only marginal for one 255 LPH pump.

 

If I get the racetronix upgraded wiring kit can I simply add a second pump. I'm sure I read about a dual pump wiring kit in GMHTP but I can't find one for my LT1.

 

Dual Walbros draw about 20 amps of current. A single Racetronix wiring harness (10 gauge) is not big enough to handle 20 amps.
Second, it sounds like you still intend to run both pumps at the same time. That is highly discouraged b/c the return line is not sized to handle the volumes it would have to deal with at low demand times. At least wire the second pump with some type of switch to trigger the second pump when you need it. Some types of switches are window switches, Hobbs switches and WOT switches.

 

Does anyone make a dual pump wiring kit

 

You might try Racetronix. I know they sell one, but I have only seen them sell it as a complete kit with the pump assembly.

 

You could easily use the stock signal wire to trigger a relay or relays to run the pumps.

 

If I run an inline pump will it still flow fuel if its not turned on. I would like to use a hobbs switch and turn it on an inline pump at 10lbs of boost.

 

No. It would have to run all the time.

 

Many people have used the Racetronix single pump harness for the first pump, then built their own harness for the second in-tank pump. Just a suggestion.

 

Can I just drill holes in the sending unit to add a second set of wires for the second pump. What do people use to seal the new holes. Are there fitting that I can stick on the stock sending unit to allow me to run -8 and -6 lines. GM quick connect fuel fittings to -6.-8 fittings.

 

I found it easier to add a sump to the tank, and run the second pump off the sump. Easy to wire, easy to control, easy to plumb.

Yes, there are compression fitting to adapt to -AN sizes. Or, since its easy to remove the pump support assembly, you could have the correct fittings brazed on.

Might want to call it the fuel pump support assembly to avoid confusion. The "sending unit" is just a small part of the assembly.