Has anyone here installed a Holley Sniper in a square body or similar vintage truck that did not come with fuel injection? If so, did you make any modifications to the tank, like install an in-tank pump, build a sump/baffle, or just slap an inline pump in the frame and go with it?

Reason for asking - I have long considered putting a Sniper on my welding truck but am hesitant because of the dual tank arrangement. It's a C30 and still has the two tiny outboard fuel tanks that got GM sued back in the day. I was doing some maintenance today and studied the directional valve for switching tanks; it switches both supply AND return. In simple terms - as long as it's between the valve and the Sniper, an inline pump and regulator could work with this system. So this afternoon, I got back online and looked up dual tank installs. There were a couple threads on the Holley forum where posters thought they were getting pump overheating and cavitation because of 'restricted' suction through the directional (tank switch) valve.

I am not really interested in pulling the bed. It's heavy af and I'd have to pull the welder, bottles, and a whole bunch of other stuff that just makes it challenging. So if this requires retrofitting in-tank pumps I'll probably just suffer with the carb a bit longer. I am curious if anyone here has installed a Sniper on a dual tank vehicle or put one in how did it go? Was it worth the effort & $$?

Pic of truck in question. It's a small block with aftermarket carb and it drives okay, but the truck gets used sparingly and you know what sitting does to carbureted engines these days. (No, I don't want to LS swap this truck, Silvy)

What carb is currently on it ?

From my experience holley's were most prone to ethanol/fuel issues especially with the power valves


I switched to edelbrock with a clear inline filter before the carb that you could alway inspect and it helped a lot.

Also the dual tanks were a problem on my truck due to trash/rust if the truck set too long.

Also if you are not driving it much i would use Startron ethanol treatment on both tanks religiously for cheap insurance.

I am an Edelbrock bro too! While I am not certain of the model I'm pretty sure it's the 1406 600cfm and has that clear inline filter too. I've had the truck since 2004 and it was on there when I got it.

The truck is so bad about losing prime. I put a new mechanical fuel filter on a while back but it still is hard to start after sitting. Well, I went and picked up an Edelbrock 12v pump that puts up about 3 psi and was going to plumb it in to help the mechanical pump out. While I was under the truck to plan all that I saw the rubber jumper lines at the tank valve were super dried out and cracked; so I replaced them. This was when I started considering the Sniper. On a later parts run I returned the aux pump to the store.

I won't bore you with all the project creep that involved spark plugs, valve cover gaskets, manifolds and stuff - suffice to say I was deep into justifying to myself that I need a Sniper EFI when I posted last night. However, while I was up all night watching the college football recap shows I found more than a couple posts from users who struggled to get their Snipers reliable with twin fuel tanks. Clearly the best way to do it means pulling the tanks and installing in-tank pumps, I just don't want to go through all that work and expense if I an avoid it.

So after church today I went back by the parts store and picked up the aux pump again. I'm going to wear it out hauling it back and forth from town to my shop. Anyway, I got all the manifold stuff worked out and I think I've saved the planet by replacing valve cover gaskets. In the next day or two I'm going to put the little lift pump in between the tank switch valve and mechanical pump. I'm hoping that and replacing dried fuel lines will make the starter breathe a sigh of relief.

I don't have much to add to the discussion other than I like that rig.

Any in-line pump will struggle to "pull". They are designed to push. Especially in-line FI pumps. You would need a modification to pull fuel from the bottom of the tanks. However, you can run a command center where the stock mechanical pump feeds a smaller tank on the inner fender that has the FI pump in it. This is the solution without pulling the bed. Your dual tank will still switch as designed.

Also, do not let the sniper run the timing, just fuel, and you'll be good to go in a day's work.

@ Burdizzo, Thank you. I love this truck and take a lot of pride in it. It still has a job to do - when something's broke it has to roll!

@ TxSquarebody - thanks for the tips. I had come to your conclusion the last time I fancied this notion but in a weak moment I started to give in to temptation. Hence this thread. However, I've come back to my senses and I'll be keeping it OG for a while longer.

To your point, in case anyone else finds this thread someday - last night I bolted that little Edelbrock aux pump to the frame and ran a hose off of it into a bucket. It pumped its little heart out, but best it could do was about 60% of a good stream, there was clearly lots of cavitation. This morning I tried the pump again and it wouldn't pump at all... it had lost its prime and like you said, it ain't getting it back from the top of the tank.

"An in-line pump will struggle to 'pull'". - TxSqaurebody circa 2025. #FACTS.

I believe the hoses that connect to the steel lines on top of the tank are as porous as the ones I found in the frame rail. Of course, it takes a contortionist to reach them - I can get my arm in there blind and feed the constant tension clamp but I can't see what I'm doing. What I think I CAN do is pull the steel line, jumper hose, and all as one piece, then replace the hose and stab it back on there.

I don't have to worry about the returns anyway - this might just work. Honestly, once I get the priming issue solved, I'm golden, truck runs like a top.

Also, because you'll appreciate, since I was there I thought I'd pull a plug and check it. Of course I broke it - so here we go, time to install a set of new plugs. I didn't realize that this truck has 202 angle plug heads. I remember my uncle telling me it has a steel crank and a (now old school, but not so 'old' when it was put in) RV cam - but had forgotten it had camel hump heads. I know this is way outdone now by better cams, vortec heads, and all... but his has been this way since the truck's first rebuild in the early 80's. It's still OG!

Centerpole90 said:

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Pic of truck in question. It's a small block with aftermarket carb and it drives okay, but the truck gets used sparingly and you know what sitting does to carbureted engines these days. (No, I don't want to LS swap this truck, Silvy)

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I had every expectation of scrolling down this thread to find a spiteful reply from Silvy telling you to LS swap.

Fitech has a solution for this. They have a small fuel module that holds the high-pressure pump in it that feeds the throttle body. The engine's low-pressure fuel pump keeps it full. This allows you to keep your standard fuel tanks and switchover valve in place. I used this on my 1970 F250 and it works pretty well. I did have a problem with vapor lock initially because the little tank is mounted in the engine bay and was getting too hot causing fuel in the tank to vaporize faster than the mechanical pump was putting fuel in. It only happened during longer periods of idling. I wrapped it in some of that sound mat material and that solved the problem. It's a pretty low-cost, low hassle way to handle dual tanks. You do need a vapor return line to one of the tanks. I just ran that to a T that I inserted into the filler hose on the first tank. The Fitech tank/pump is probably compatible with the Holly if you don't want to go with the full Fitech solution.

This is exactly the kind of info I was looking for! Thank you so much.

Dang, I had about talked myself out of this....

How do you like the EFI on your F250? Give us the deets please.