5.3 LS Swap Build For 80s K5 Blazers

[88blazerboy]

Thanks for the post! WhiteLs1 has some good information and parts numbers for building up a 5.3. I came across Vetteworks and the fuel ring adapter about a month ago when I was researching how to build the high pressure fuel system. I'm pretty sure the company is located in Vegas too, so maybe it didn't cost as much for locals. I spoke with one of the owners about the part, and in short, the new ring can be TIG welded on or glued after the old ring has been cut out. I'm glad it works for some, but I personally think this is a very expensive and unnecessary rout. There are several aftermarket universal in-tank fuel pumps that will drop right into the Blazer's fuel sending unit and work fine. i just haven't determined which one will work the best yet. If anyone is interested in the Vettework ring, here is the link: http://www.vetteworksonline.net/cata...php?cPath=9_68 .

[88blazerboy]

In this post, I'm going to deal with the conversion to a higher pressure fuel system from TBI to EFI. I'm feeling pretty confident at this point that I have the right idea for my own setup; however, I'm including additional information that should be universal and apply to anyone's swap. I’ll be attaching a link to my own conversion video in about a month or so because I don’t like anyone else’s.

For me, my 88 Blazer has TBI, so it already has a baffle tank that will help reduce fuel starvation from gas sloshing around in the tank. If you have a tank that does not have a baffle in it, it's probably in your best interest to get one, either from a newer model that will fit right, or from a company that builds aftermarket tanks. One company is Tanksinc.com at www.tanksinc.com/. They have a large line of products from tanks to pumps, regulators, lines, and such. Unfortunately, their aftermarket baffle tank selection for trucks is quite limited, but they have other products like fuel sumps that can be installed in a tank without baffles for under $300.00, so in my opinion, they have most of the stuff for any conversion. They also have fuel supply diagrams for just about every setup you can think of in jpg. Files. I'll include the diagram from them that I'll be using shortly.

Another option for salvaging your stock fuel tank is to buy a fuel tank ring kit from Vetteworksonline.net at [URL=" www.vetteworksonline.net/[/URL]. This part allows you to hack up and modify your stock fuel pump cam (ring) with a modified one that will take an early 2000s efi Votec fuel pump. According to one of the workers at vetteworks, the kits can be TIG welded or glued to the stock tanks (depending on their material), and I have read several threads that have gone this rout. Here is a blog build on a vintage K5 Blazer that uses Vettework’s ring kit: [URL="http://morecoffee.me/index.php?view=bulletin&blog=90/[/URL]. Here is a video from NewVegas who also has a thread on this forum: http://<a href="https://www.youtube....vlLQ#t=110</a> . To me, this rout looks overly expensive and overly complicated.

Some Gen IV motors have single fuel lines and some have double. I don't know about the Gen III motors, but if you are not sure about what you have, then examine your fuel rails: if there is one fuel line coming off the fuel rail, then you have a single. If there are two fuel lines (one on each fuel rail), then you have a double, and in that case, you probably have a fuel regulator built into the engine - at least for the Gen IV motors. I have a single line and will need to build a fuel supply that uses a fuel regulator and 3/8 (AN 6) lines. The size of your lines and the fuel pump will vary depending on you motor’s HP, but the design of the fuel supply shouldn’t change much.

I was going to salvage some the Blazer's steel fuel lines for the swap, but the price of new, steel braided fuel lines and fast connectors are cheap, as well as durable, so I'm trashing the old metal lines. Here is the diagram of the system I will be using: . The website has many other system diagrams if this one does not seem appealing. The "filter" in the image is a Corvette fuel filter/regulator - usually a WIX-33737 for about $45, or you could use a LS9904-KIT from Tanksinc.com for around $70 with the bracket and quick connectors already attached. I’ll keep my tank and fuel sending kit and drop an in-tank pump; either the HFP 255LPH Fuel Pump Chevrolet K10 Pickup 4x4 1988 - 1995 (HFP-343) or the255LPH GM Walbro Alternative Fuel Pump w/ Venturi Tube (HFP-368H). According to the manufactures, both pumps will install without any weird modifications (e.g. cutting, gluing, welding), and they will produce a little over 60psi. My engine will only have about 320 HP, so if you have more HP, you will likely need a different fuel pump and bigger fuel lines. From my pump, I’ll have my supply line leaving my tank and flowing to the Corvette fuel filter/regulator which will be mounted to the side-frame of my truck on the passenger side. From the filter/regulator, one line will return back to the tank, and the other will flow directly to the fuel rail port on the engine. I might include a couple additional micon filters in the circuit as well. Here is a video that show what the fuel supply line will look like. For the first two minutes, the guy just gives a sales pitch, but after that, it becomes visually useful: https://www.youtube.com/watch?v=85xJa_Zvkp8 .

Until I post the video of my own fuel supply conversion, I think this about covers what I know about the subject. Feel free to reply or ridicule.

Lastly, here are a few other links for support if you are new to designing fuel supplies like I am. The subject seems to come up a lot on threads:

https://www.youtube.com/watch?v=XwGgy5vP_DY Basic 9 minute video on how EFI works.
https://www.youtube.com/watch?v=qAAP9SOHu-I A somewhat informative video on choices to use for designing efi systems. Nothing specific here, though, and it’s an advertisement for Fast Fuel.
http://<a href="https://www.youtube....HgZ1YTMqw8</a> Another episode of Chuck and his $10K “budget” LS swap with premium Hooker/Holly parts. If you don’t know how to cut lines and attach fuel compression rings, it might help – maybe.