1971 5.3/4L60E first time swap
 

Hey guys glad to be here! just created an account today, been lurking for months getting ideas! Me and my dad are in the process of doing our first swap together, its so exciting. Truck was painted 1991 by my dad and a friend and the old 350/T350 just isn't cutting it anymore. so we are taking a plunge. I will try to keep this somewhat up to date. only question i have is A/C wiring and some fan questions for later down the road.

And yes the machine shop installed 4 pistons backwards, they came to our house and picked it up, and also fixed the reluctor wheel they had bent.

Will be pulling old motor and transmission after thanksgiving!

Re: 1971 5.3/4L60E first time swap
 

Here is where I'm a bit lost with the A/C and fans. our stand alone harness didnt come with the best directions....

In the near future i wanna get a Vintage air set up and use the PCM to turn on fans, up the idle, and kill compressor under WOT. but from what ive read its hard to do that? also we only got A/C clutch and A/C request signal wiring and not sure what to do with request wire once we get to that point

The two big blue wires are for the fans, color code was wrong for green. wiring seems small as well, im rusty with Relays!

Re: 1971 5.3/4L60E first time swap
 

made some progress today, maybe another hour tomorrow and old power plant should be on the floor!

Re: 1971 5.3/4L60E first time swap
 

Welcome, looks like a nice project- will be tagging along

Re: 1971 5.3/4L60E first time swap
 

Motor came out without a hitch today, friends engine pulling system really came in handy! tomorrow will be cleaning up engine bay and paint where needed. Purple power sure does an amazing job cutting thru the grease and crud!

for guys who have done the ls swap, can I use the 12volt wire that feeds the HEI Distributor for the pcm key on/run? its one of the only wires im aware of that has power during cranking and key on.

Re: 1971 5.3/4L60E first time swap
 

Didn't get a chance to stab motor in today.

I spent the entire day going through the wiring and removing what i didn't need for the swap. Found some wiring for the Ford solenoid that had been installed way wrong (see attached image) I have no idea how it started and how we didnt have a fire.... someone had used the purple/orange wire that splits into 2 yellow wires the improper way!!! This truck is a wiring nightmare so far... :whine:

Moved the upper horn to passenger side to make room for Driver side battery tray i ordered from Scotts Super Trucks.

Removed all wiring that went to our charging system except the black/white wire for the cluster (which will probably not be used anyways)

Also moved all the power distribution to the driver side.

Re: 1971 5.3/4L60E first time swap
 

Do yourself a favor and read this thread. Eric is a great cat and a member here also. LOTS of tips and tricks. Good luck!

Re: 1971 5.3/4L60E first time swap
 

Thanks man! I have spent hours upon hours looking through the threads getting ideas! Its exhausting lol. Have a lot of wiring diagrams memorized now. Not looking forward to yanking out the cluster assembly to clean up the rat nest behind it.

Re: 1971 5.3/4L60E first time swap
 

Since i work nights, I only get to have Saturday to work on our little project.

got the Driver side battery tray in the mail yesterday and had just enough time to take it out of box and realize our front support doesn't have the mounting holes I thought it would have, oh well!

correct me if im wrong but didn't 69 up trucks have the option for the tray?

Re: 1971 5.3/4L60E first time swap
 

Heres a better look at the Beauty we working on.

Hard to believe the paint is almost 27 years old

Re: 1971 5.3/4L60E first time swap
 

Truck and motor look great. I'm following along so if you get that wiring issues figured out post it for the rest of us.

Re: 1971 5.3/4L60E first time swap
 

For starters we did not get motor and transmission in tonight, got them bolted together though! Dad wanted to paint the frame rails and cross member with some POR-15 since it'll be a while before truck gets restored again

Also learned a fun fact today while under the dash, our truck had a Anti-Dieseling relay wired into A/C wiring.

1. painting done

2. used a Dremel to get the stock 5.3 throttle cable to fit through the firewall, which it snaps into the pedal like it was made for it lol

3. found a nice burnt plug on the Heat/air switch, will be good to remove all the A/C wiring once we get vintage air installed.

4.Motor and tranny bolted together.

Re: 1971 5.3/4L60E first time swap
 

Here's my plan for the fuel system, ordered a 1972 C10 sending Unit from rockauto, with 3/8 feed and 5/16 vent (going to be my Return)

Ordered 15 feet of stainless steel braided fuel line from Jegs.

Went with walboro 255 with a pre and post filter, and just gonna run 5/16 EFI rated fuel line back to the tank

trying to decide on AN fittings was not easy, going to be my first time messing with them, heres a diagram i drew up to get my mind around what i would need lol

Edit: in my drawing i show a 10 micron fuel filter as a pre, I realized my error after the fact that i ordered it. i ordered a 100 micron filter from amazon (why are the larger partical filters so dang expensive?!?!)

Re: 1971 5.3/4L60E first time swap
 

This is what I was thinking of doing for my swap too. Do you have a link for the sending unit you bought?

Re: 1971 5.3/4L60E first time swap
 

Heres that link! I figured it was would save me money in the long run.
https://www.rockauto.com/en/catalog/...ding+unit,4436

Re: 1971 5.3/4L60E first time swap
 

looks like you got a good start on your swap so far. . I think your fuel set up might have a problem with stalling if you run the tank low. Im no expert just giving you a heads up if you wish to look into it further before you finish. . . I've seen the stock tanks used, but they had a sump modified into them so they wouldn't starve the pump of fuel.

not trying to pick it apart, im no expert just what I've read. .Also read if you wanna run this type of set up just keep it above a 1/2 tank at all times and shouldn't have issues. Looking forward to seeing the rest of the swap

Re: 1971 5.3/4L60E first time swap
 

Ive read that too as well, ive heard horror stories and some who have had success to it. If it comes to it, i'll take it somewhere to have the feed line welded to the bottom of the tank. The rear mounted tank isnt an option for us at the moment either.

Re: 1971 5.3/4L60E first time swap
 

this guy had a unique solution depending on your budget. . seemed to work for his build.
http://67-72chevytrucks.com/vboard/s...d.php?t=239446

Also someone mentioned if you do the set up as you are, to bend the return line away from the fuel pick up to avoid aeration at the pickup tube. Good luck either way, look forward to seeing how it works out.

Re: 1971 5.3/4L60E first time swap
 

I like the idea of having a small holding tank! It might come to that.

Thanks for the advise!

Re: 1971 5.3/4L60E first time swap
 

Not much progress this week so far, still waiting on parts to come in the mail. Did dig up some pictures from the late 1980's when dad bought the truck, it was used on a farm from what i remember being told (Even had a goose neck hook up in the bed) . Then 1991, around when i was born, him and and friend restored it.

sorry not the best pics, but they are old! lol

The headers we ordered are on back order till late December, guess we wont be starting it this weekend :(

Re: 1971 5.3/4L60E first time swap
 

Lol. This is a cool thread. I like to see newbies take the LSx plunge. Your truck is going to fly with the new power plant. Post vid when you start it up. I didn't understand your CAD drawing but you can modify you stock c10 sending unit to accept a in-tank fuel pump. For start up, the external tank is a great Idea. Just to check out the engine, you can use the stock exhaust. For filters, what type of fuel rails are you using? You may not need those filters. And lastly, for an ignition power source, if you have one, use a test light to find out which wires are hot. You can check them at the bulk head. I always check my power sources because I don't want any unknown wires floating around in my engine bay. I've had a few electrical mishaps trying to figure this LSx stuff out. Good luck. I'll be following this thread. If you have questions ask away. It seems you are well on your way.

Re: 1971 5.3/4L60E first time swap
 

With your filter setup, check the microns. 10 maybe too extreme. Your pic shows you have a filter on the fuel rail. You don't want to restrict fuel flow.

Re: 1971 5.3/4L60E first time swap
 

Its not technically my first plunge lol. (This is just a whole new can of worms to mess with) Did ls1 swap to my bird about 4 years ago :) was not gonna miss a chance to film her first start! Ive actually got all the useless wires removed from the engine bay and labeled each wire as i removed them

Fun fact- 5.3 bored .02 over, scat rods, brian tooley stage one cam, upgraded rockers

Re: 1971 5.3/4L60E first time swap
 

I actually learned the next day that i should not have ordered a 10 micron filter so i found a 100 micron filter and ordered it right away! (They are pricey too)

I dont see where you see a filter on the fuel rail... ik theres not one there lol

Re: 1971 5.3/4L60E first time swap
 

@evanhall19 that circle silver thingy, that's a regulator with a filter screen inside. what you have listed above ^^^ should work. the summit filters work great. Good luck.