HELP with 1987 305 TBI to 5.3/4L60e conversion

[Dustin Riibe]

Hey guys I’m new to the site. This is my first post of any kind. I have a 87 k10 305 tbi truck. It has dual tanks. I’m about to begin my 5.3/4L60 swap. Has anyone done this on a dual tank 87 with a tbi? I need help w the fuel system. I know about swapping the in tank pumps to high pressure units... but what about the return lines? How do you go about running the return line system on dual tanks? In fact... how bout the lines in general? What have ppl done? Also, the wiring... I assume more people are removing the tbi ecm and using those power and ground wires to power a stand alone LS harness somehow? This is my first LS swap. Anything helps here. I ordered dingo engine mounts and am planning to have Howell make my harness. My main issue is the fuel system.

 

[Preston]

Welcome to GMSB from Virginia

I bought an 84 K10 as a project with a 5.3 engine I decided to not go that route because of all the adapters needed to get the 4x4 to work. Doesn’t the 87 already have TBI? I need the ECM from a 87 Suburban ( that’s what my running gear came out of) please post your project and keep asking questions there are many guys here that can help you with them

 

[1985c20]

The 87 should already have the return lines plumbed through the tank switching valve since it’s tbi. Wiring yes I think you’re going to have to remove all the old and use the LS things.

 

[Charlie]

 

[dvdswan]

Welcome to the site.

 

[Madhorn]

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Welcome. Do you have a short bed or long bed truck? 16 or 20 gallon tanks? I just went threw all this with my 77. Being a short bed with dual 16 gallon tanks I have had lots of issues with switching valves, switches and sending units before the swap. So when I did my LS swap I opted to use one 16 gallon tank to keep things simple. Only down side is having to stop for gas more often. A 20 gallon would not be bad In hind sight/more budget I would have installed a 30 gallon suburban tank behind the rear axle. I am not saying two tanks are impossible, just more complicated. Is your donor engine have fuel return or returnless?

 

[hip2bsquare]

HI,
I have a '86 SWB with dual tanks as well and I am in the beginning stages of a LS/LT swap. i would like to keep the dual tank theme too, I noticed on my truck that there appears to be a smaller diameter return line that runs parrallel to the bigger primary feed line. unfortunately my truck did not have a TBI motor (when purchased it had a carbed 305 - aarrgg). my thought is that the "delivery" setup would be the same as the year model of the truck (86-87), but just have to account for the HP fuel requirements for the LS/LT motor? i would think that the return line back to the the tank would be the same size used on the swapped motor setup? those are my thoughts... maybe help a little bit....