5.3 LS SWAP 82 C10 QUESTIONS

For the life of me I cannot find a thread with the question I need so if its already been discussed I am sorry, decided to just go ahead and do a 5.3 swap on my c10 cause my dad did make a good point of not spending the 2k on rebuilding the 305 and just go ahead and do the LS I already wanted to do so I am essentially saving the 2k by ditching the 305. I want to run a carb set up just because its simple and in a sense the cheaper way to get the LS up and running. Ive read alot of the forums that talk about the fuel pump issue which I know regardless that its going to have to be adressed one way or another. If possible I want to avoid replacing the fuel tanks with 1987 ones for the fuel pump and baffles. Would it be possible just to run an aftermarket frame mounted fuel pump? I also just watched one of the Brothers truck and parts videos and I guess they have a fuel pump that works with 73 to 87 stock fuel tanks and has a "soaker" to solve the issue of losing power while cornering. Anyone have any experience with any of this? Again apologies in advance if this has already been discussed.

I know Holley makes retrofit fuel pumps with a big sock on the bottom that works without baffling. They were stupid expensive when I was looking. I was able to do my entire fuel system with new baffled tanks, high pressure lines, sending units, pumps, and the switch in the cab. For less than two of the special Holley units was going to cost

If you are running a carbureator,no need for a baffled tank. I'd prefer an intank pump,but for cheap and easy run a good external pump as close to the tank and as low as you can get it. Power it with a fuel pump relay, pickup pump power for the relay at the battery,to reduce potential volt drop. Run your factory fuel lines, install a bypass regulator close to the original fuel pump location. This will give your new fuel pump,bypass to keep it cool and not deadhead it,with minimal work. As for wiring the pump and relay,use a common 4 prong relay,run terminal 30 to the Battery 12v post 87 to the fuel pump, 85 to the alternator exciter wire 86 to ground. This way the pump should recieve a strong consistent 12volt source,only when the engine is running.

If you're gonna run a carb, just do a warmed over 350 or 383 setup. The whole reason to LS swap is to gain fuel injection and a OD trans to get modern drivability in a classic truck. Putting a carb on an LS is like putting a model T engine in a '55 Hemi Chrysler, makes no sense. Plus between buying the carb, the manifold, the MSD igintion setup, you're in it the same or more than a proper swap harness to just use the OE fuel injection.

Same argument for the fuel pump. That Holley Fuel Mat thing is expensive as hell. Do '87 tanks, senders and Walboro 255 pumps and a fuelie switch valve for an '87 truck way cheaper. In-tank pumps are always more reliable because they get cooled by the fuel. If you're hell bent on a carb setup, you can do the fuelie setup and just mount a regulator on the carb or on the firewall with a return line to dial back the pressure.

Get a junkyard motor with the intake/computer/accessories and everything. Go through it if you wish, or if you trust it, do an external reseal and run it. When I did mine, I knew and trusted the guy I got it from. 104k mile takeout 5.3 motor and trans that ran great. I pulled the intake/oil pan/front and rear covers/heads off, inspected the bottom end and determined it to be good. Rebuilt the heads, threw a cam in, buttoned it up and threw it in the truck with the 4L60 and a 3000 stall converter. Did a PSI harness (I'd suggest a BP Automotive harness now, PSI has fallen from the top for various reasons), just a few wires to hook up/merge with the stock ones, did the '87 tank/sender/Walboro 255 pump, made my own lines with an Amazon braided -6 AN setup, Tejas Steelworks engine/trans mounts and fan shroud for dual 13" spal fans and it's been dead nuts reliable for 50k miles and 4 years now. Also make sure to get your fuel injectors cleaned/flowed or buy new ones, don't wanna hydro the motor due to a hung injector.

Unless you own a carb tuning business and know everything there is to know about them, running a carb will not actually be cheaper or easier or faster than factory EFI. And the electronics involved in making an LS run on a carb is generally more complicated than the electronics to run the full EFI. 87 tanks are the correct option. If you want to skate by, you can run an external pump like Rick spells out, but I'll agree the fuel mat stuff is insane when there's a readily available OEM solution to the problem. Its a different story if you are LS swapping a handmade, one-off European car and need to use the original tank because nothing else exists, but when the vehicle came with factory EFI tanks, get them.

If cash is tight, get one and get used to refilling the tank more often?

What Hucked said. I will add to it that if you have the means and the space, buy a side or rear wrecked doner vehicle for the LS swap, you can save a lot on incidentals going that route and you are fairly certain it was running/driving vehicle when it was "parked". Depending on the look you are going for with the swap you can reuse ALOT of the engine compartment. I have even heard of salvage yards selling you the doner and then buying it back at scrap prices when you're done.