Mark V fuel delivery

[slimneverdies]

Hey guys, I'm running into a scenario where I'm putting a Mark V 454 into my 78 C30. The tanks look to be original for 78 judging by the lines going in so I take it there shouldn't be any electric pumps in the tanks. From what it looks like this motor doesn't have provisions for a mechanical pump on the front so I take it I have to put an electric pump inline. I'm curious to know if I would need two electric fuel pumps since this trucks has dual tanks and how do I wire the pumps up with the switch so only the pump/tank that's in use will have power?????

Thanks
Slim

[jetmech85]

I would think an aftermarket electric pump installed inline after the tank switching valve and wired to be hot when the key is on. Only need one pump that is taking the place of one mechanical pump.

[motornut]

Originally Posted by slimneverdies

Hey guys, I'm running into a scenario where I'm putting a Mark V 454 into my 78 C30. The tanks look to be original for 78 judging by the lines going in so I take it there shouldn't be any electric pumps in the tanks. From what it looks like this motor doesn't have provisions for a mechanical pump on the front so I take it I have to put an electric pump inline. I'm curious to know if I would need two electric fuel pumps since this trucks has dual tanks and how do I wire the pumps up with the switch so only the pump/tank that's in use will have power?????

Thanks
Slim

do you need a return line?(my 78 didn't have one,79 does)
stock pump, would be 2,1 in each tank ,might be worth getting F.I. parts/truck?

[jetmech85]

Yes, I guess the question I forgot to ask is this going to be a carb or FI? Fuel injection has to have a return line and carb does not but needs to be pressure regulated to keep from pushing the needle valve open.

[bnoon]

My two carbed trucks had return lines on the frame. They were both 3/8" for the feed and 5/16 on the return. Note that the return line was down by the mechanical fuel pump FYI and not up near the carb feed line.

The only problem with running one pump inline for fuel injected is if you ever run out of fuel, you may have issues priming fuel to the pump. Personally though, I've never had any issues getting them to suck fuel if you keep them within about 18 inches of the tank, which could be difficult with dual tanks.

[slimneverdies]

No return line or pumps in the tanks. It has a carb on it and Im testing the fuel pump next to the firewall now. If I only need one pump after the switch this will be an easy upgrade. Thanks

[bnoon]

Don't mount it up on the firewall. At least keep it down low on the frame and close to the tanks!

[slimneverdies]

Originally Posted by bnoon

Don't mount it up on the firewall. At least keep it down low on the frame and close to the tanks!

I was just testing it up on the firewall to get the BB running. I'll keep it the recommended 12" away from the tanks...