Inline Fuel Pump Location on 1st Gen Blazer

[CJM72]

I have a question for you experienced LS swappers. I have a 72 Blazer that has an LQ9 installed. I'm finally getting to the fuel system install. I have a brand new original style tank with the neck swapped over, an inline walbro pump, corvette regulator, and nylon lines and quick connect fittings. I'm about to mount the pump and run the lines and I'm confused about where to put it.

I can put it close to the tank, but this puts it near the top of the tank. Or I can mount it about 3 feet father forward where the frame drops down and get it down a little lower. I was convinced the inline pump would be fine, but most people using them successfully have in-cab truck tanks, so the pump is mounted below the tank. Unfortunately, the money is spent and I'm not interested in buying an intank pump at this point.

So what do you think: Close as possible to the tank and high, or 3 feet farther forward and closer to the midline of the tank? Will either work?

[mongocanfly]

I have mine mouted above the tank....as close to the tank as possible will make life easier on the pump

[CJM72]

Thanks Mongo. That was my gut feeling as well. I'm already sucking fuel up the sending unit. Minimizing the distance is probably more important than height. Hope you've gotten some good miles out of that pump!

[mongocanfly]

Over 20k and still going

[Madkidd007]

I agree with shortest distance possible but at the same time I would go low even if it required going further from the tank. Think of it this way, up high it has to suck to prime, now when you siphon gas think about how when the hose end is below the fuel level it will come out on its own. The thought process is if it’s below the fuel level it won’t have to suck to prime as fuel will naturally drain to the lower level. Ofcourse this thought all depends on if you can get the pump to the lowest fuel level you will ever have

[CJM72]

Originally Posted by Madkidd007

I agree with shortest distance possible but at the same time I would go low even if it required going further from the tank. Think of it this way, up high it has to suck to prime, now when you siphon gas think about how when the hose end is below the fuel level it will come out on its own. The thought process is if it’s below the fuel level it won’t have to suck to prime as fuel will naturally drain to the lower level. Ofcourse this thought all depends on if you can get the pump to the lowest fuel level you will ever have

Yes, I agree with all this in principle. The challenge with an inline pump on a blazer is that the tank basically hangs below the frame. To get the pump 'low enough' you're either moving it about 4ft forward, or you have to create a bracket to drop it down closer to the tank that would leave it very exposed to exhaust piping and road debris. In hindsight, I should have spent a little extra money on an in-tank pump, but the costs on these swaps really add up if you try to do everything the most correct way!

[Madkidd007]

Originally Posted by CJM72

Yes, I agree with all this in principle. The challenge with an inline pump on a blazer is that the tank basically hangs below the frame. To get the pump 'low enough' you're either moving it about 4ft forward, or you have to create a bracket to drop it down closer to the tank that would leave it very exposed to exhaust piping and road debris. In hindsight, I should have spent a little extra money on an in-tank pump, but the costs on these swaps really add up if you try to do everything the most correct way!

I feel ya on it adds up, my cummins did that too me but that’s kinda my fault. Not to respond with the smart guy answer but possibly reach out to walbro themselves as I’m sure they’ve seen it all and know which the design is best set up as

[mongocanfly]

Mount it close to the tank and it'll be fine...