74 c10 5.3 swap questions

[ivorton74]

I want to do this swap in the future and im just doin some homework. I have a few questions about the swap especially in these early squarebody c10s.

1. So I'm gonna do a 5.3/4l60e swap.The truck has a 350/th350 combo in it now. the truck is a longbed c10. Will I have to shorten the driveshaft? It has a one piece shaft in it. Also can I use the stock trans crossmember? This will be a budget swap so I dont want to have to get a new crossmember fab'd.

2. What is the best adapter plates to use? Im trying to choose between dirty dingo and transdapt.

3. How hard it is to take the harness off the motor? Where's the best place to get the harness redone and ecm reflashed?

4. Can I use the 74 gas tank with a electric fuel pump or do I have to use one from an 87? How do I set the fuel system up?

5. I want to stick with the original 100MPH speedo instead of the 85MPH speedo from the newer trucks. How do I make this work?

6. Which headers will fit my truck without cutting the frame?

7. Im looking for some cheaper ways to get more power from the 5.3. Any suggestions?

8. Can I use my stock rad or do I need a different one? I read the fboday rads and fans can work.

Hope u guys dont think these are too many questions but I need as much info as possible. This will be the first time Im attempting something like this. I may have more questions so bear with me.

[BR3W CITY]

Originally Posted by ivorton74

I want to do this swap in the future and im just doin some homework. I have a few questions about the swap especially in these early squarebody c10s.

2. What is the best adapter plates to use? Im trying to choose between dirty dingo and transdapt.

I used the transdapts, cheap and simple. Dingos are nice but spendy unless you need them for a 4wd.

3. How hard it is to take the harness off the motor? Where's the best place to get the harness redone and ecm reflashed?

You just need to unplug everything, biggest pain is undoing grounds and un-snaking the harness from stuff, depending on what its coming out of. Don't do a mail order flash if you can avoid it, find a tuner near you who will unlock stuff like vats from the ecm, then get it dyno tuned.

5. I want to stick with the original 100MPH speedo instead of the 85MPH speedo from the newer trucks. How do I make this work?

If its a mechanical speedo, you need to run something like a CableX to get the electronic output to work with your speedo

6. Which headers will fit my truck without cutting the frame?

tbss, gto, ls3, and Doug Thorley swap headers should work, and some people have worked with fbody manifolds and a few varieties of shorty and swap headers from Hooker.

7. Im looking for some cheaper ways to get more power from the 5.3. Any suggestions?

Subjective....whats your idea of cheap, and how much are you looking to get? Cam swaps offer good gains, but you need to do the correct supporting mods.

8. Can I use my stock rad or do I need a different one? I read the fboday rads and fans can work.

I used a sbc radiator for mine, if you can get hoses to work it should be fine, though a steam port will help if you have nowhere else to run it.

Hope u guys dont think these are too many questions but I need as much info as possible. This will be the first time Im attempting something like this. I may have more questions so bear with me.

search, read, spend some time on a little research. There is lots of little stuff like drive by wire, steam ports, tuning etc that also needs to be deal with. And fwiw, you will spend more than you intend, so although its a budget project, be prepared to open your wallet at some point.

Hope any of that helps. Be patient, try to make a parts/tasks list etc, know what you need the first time to avoid wasted money, but understand sometimes you just have to make stuff work, or accept that things that SHOULD have worked didn't/don't etc.
Good luck.

[ls1nova71]

Looks like BR3W answered most of your questions, so I'll just hit the ones he didnt.
The driveshaft will most likley need to be shortened, but it may need to have one made due to the fact that some of the driveshafts in those years were kind of tapered on the ends so when you cut the end off to shorten it, where you would need to weld it back on would be too big for it.

Crossmembers can usually be slid back some and new holes drilled in the frame, but I am not surer if that is possible on the square bodies, you'll need to crawl under there and look.

As for the gas tank, I would highly reccomend getting the 87 tank. You'll be happier in the long run. You'll need the sender from an 87 also and a good quality pump. Some people use external pumps, but aside from being noisy and usually having a shorter life, you also have to deal with the possibility of vapor lock when you are trying to pull fuel out of a tank. Electric pumps are better suited at pushing fuel.

Depending on what year your engine is, returnlesss fuel rail or return style will determine what kind of filter or filter/regulator you will need.
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[ivorton74]

Thanks fellas for ur input. So I made a list...
1. complete 5.3/4l60e (obviously)
2. transdapt 4572 mount adapters
3. 87 fuel tank and sending unit
4. walbro 255 fuel pump
5. corvette filter/regulator
6. cold air intake
7. cable x for the speedometer

still have to decide where to get my harness and ecm done. I've seen standalone harnesses from speartech,painless,psi and current performance but they just so pricey man. I live in South Dakota..there's nobody around here who does wiring and ecms so any suggestions will be appreciated. Also have to figure out which headers to use. I think I'm gonna stick with the stock radiator..although the one in the truck right now is kinda leaky so I'll get a new one.
Thats about it I guess. Let me know if I may need anything else.

[Jonboy]

I am getting ready to do a 5.3/4L60E in my '74 as well. I did things a little differently, but you can use what you want to.

1. For the driveshaft, if you have a long tailshaft (9" ext. housing), your existing driveshaft will work. I swapped an '87 5.7 TBI/700R4 in mine a whiloe back, and the driveshaft and crossmember worked fine. You will have to move the crosmamber back a few inches, though. You can keep the factory linkage with the 4L60E by using the bracket that bolts to the trans.

2. I wanted to keep the factory look, so I used a cluster from a 90-91 R/V body. If you go this route, make sure it is the electric one (no speedo cable input). You can run the signal from the PCM to this cluster. It is 85 MPH, though.

3. I used the Dirty Dingo mounts. This may just be preference, but I wanted the adjustability to make sure I didn't have to mess with the driveshaft.

3. Similar with the harness. Instead of taking a chance on 10 year old connectors, I went with an aftermarket harness and PCM reflash from www.fuelinjection.com . I had used Robert's harness when I put the TBI engine in, and it was a quality piece, especially for the money. I sent him my pedal, TAC, and ECM, and he tested them with the harness also. The other bonus of this harness is that it is long enough to install under the seat.

3. I had the luxury of having an '87 parts truck to rob the fuel system out of for my TBI transplant. It looks like I will be able to use most of the lines, as well as the tank. I am using a return style setup, as it was already on my engine (2001 Yukon). Planning on using an EP381 Delco pump on it as well.

4. I am planning on using the original radiator from the truck and engine driven fan from the Yukon. It's free, so I figure I will give it a shot. I am pretty sure the OEM spec radiator hoses for your donor will be correct.

5. I am also hoping that the original manifolds from my engine will work as well. Crossing that bridge when I get to it.

6. I am using a Vintage Air Gen IV kit in my truck already, so I bought a kit to mount the Sanden compressor high. This will help the engine mount situation as well.

I know my numbered points don't exactly match up to your questions, they are just observations I have made in my research.

[6.0 1955]

Do the harness yourself. If you get a dbw motor make sure you get the tac module, wiring from tac module to pedal and the pedal. The wiring is really not bad. Just take your time and remember pink wires are all ignition, orange wires go to battery positive, and then the ground wires. There's some good websites out there that almost walk you through it step by step. Find a tuner that is close
to you and ask him/her what they prefer to be left in the harness to program the ECM.
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[ivorton74]

Originally Posted by Jonboy

I am getting ready to do a 5.3/4L60E in my '74 as well. I did things a little differently, but you can use what you want to.

1. For the driveshaft, if you have a long tailshaft (9" ext. housing), your existing driveshaft will work. I swapped an '87 5.7 TBI/700R4 in mine a whiloe back, and the driveshaft and crossmember worked fine. You will have to move the crosmamber back a few inches, though. You can keep the factory linkage with the 4L60E by using the bracket that bolts to the trans.

2. I wanted to keep the factory look, so I used a cluster from a 90-91 R/V body. If you go this route, make sure it is the electric one (no speedo cable input). You can run the signal from the PCM to this cluster. It is 85 MPH, though.

3. I used the Dirty Dingo mounts. This may just be preference, but I wanted the adjustability to make sure I didn't have to mess with the driveshaft.

3. Similar with the harness. Instead of taking a chance on 10 year old connectors, I went with an aftermarket harness and PCM reflash from www.fuelinjection.com . I had used Robert's harness when I put the TBI engine in, and it was a quality piece, especially for the money. I sent him my pedal, TAC, and ECM, and he tested them with the harness also. The other bonus of this harness is that it is long enough to install under the seat.

3. I had the luxury of having an '87 parts truck to rob the fuel system out of for my TBI transplant. It looks like I will be able to use most of the lines, as well as the tank. I am using a return style setup, as it was already on my engine (2001 Yukon). Planning on using an EP381 Delco pump on it as well.

4. I am planning on using the original radiator from the truck and engine driven fan from the Yukon. It's free, so I figure I will give it a shot. I am pretty sure the OEM spec radiator hoses for your donor will be correct.

5. I am also hoping that the original manifolds from my engine will work as well. Crossing that bridge when I get to it.

6. I am using a Vintage Air Gen IV kit in my truck already, so I bought a kit to mount the Sanden compressor high. This will help the engine mount situation as well.

I know my numbered points don't exactly match up to your questions, they are just observations I have made in my research.

Good observations man. Thanks for the info. My driveshaft looks long to me so maybe it'll work. Im still wondering if i should use the dirty dingo mounts instead. I read about having some issues adjusting those ones so I dont know. I would like to keep the engine clutch fans also instead of using electric fans. I hope the stock manifolds fit too.I plan on getting headers but after the swap is done.Let me know if they fit your truck. I dont think I'll be keeping the a/c compressor since my truck doesnt have a/c at all. I'll just take it off the motor. It'll probably free up some extra horsepower. I'll check out that site you mentioned about the harness. I wish I can get me a donor truck for the gas tank and stuff. I hope I can find an 87 gas tank for a reasonable price.Oh yeah..Im gonna be using a b&m hammer floor shifter and not the column shifter.

btw is your truck a long bed or short bed?

[68GMCCustom]

I almost got that shifter and bought their Truck Mega Shifter instead. Sometime I wish I'd gotten the Hammer instead...tho I think they make the stuff to convert it.

[Jonboy]

Originally Posted by ivorton74

Good observations man. Thanks for the info. My driveshaft looks long to me so maybe it'll work. Im still wondering if i should use the dirty dingo mounts instead. I read about having some issues adjusting those ones so I dont know. I would like to keep the engine clutch fans also instead of using electric fans. I hope the stock manifolds fit too.I plan on getting headers but after the swap is done.Let me know if they fit your truck. I dont think I'll be keeping the a/c compressor since my truck doesnt have a/c at all. I'll just take it off the motor. It'll probably free up some extra horsepower. I'll check out that site you mentioned about the harness. I wish I can get me a donor truck for the gas tank and stuff. I hope I can find an 87 gas tank for a reasonable price.Oh yeah..Im gonna be using a b&m hammer floor shifter and not the column shifter.

btw is your truck a long bed or short bed?

Mine is a short bed. If you don't need the A/C compressor, it is simple to get rid of. The Compressor has it's own belt, tensioner, and bracket. Unbolt the compressor, then remove the bracket. You get to retain the original serpentine belt.

[BR3W CITY]

just a heads up, unless you guys have more room between your framerails than my 66, using stock truck manifolds may prove cumbersome. You might be able to fit them in, but usually you'll have to break out some tools and trim/grind the "bump" down and possibly trim one of the tips on the flange to clear. I test fit them on mine, and that was the only way it even looked possible (but no way it would fit in my case)

[ivorton74]

@jonboy...thats another things thats cleared up thanks to u. I was wondering about the a/c compressor and the belts. one more thing i dont have to worry about now lol. Im assuming my drive shaft is longer since my truck is a long bed. so maybe it'll fit with shortening it.Maybe I should use the dirty dingo mounts instead since its adjustable.
@ brewcity...thats my biggest concern..that header...i know i may have problems with it.

[Jonboy]

Brew, the rails are similar, I think. I didn't want to spring for a set of headers until I knew for sure they wouldn't work. I was looking at the new Hooker cast iron headers, but I will try what I have first. Minor trimming isn't really a problem, but major trimming will be.

Ivorton, the driveshaft should be the same in relation to the truck. If it fit with a long tailshaft TH350, it should work with the 4L60E.

One small deviation I will be doing on mine is a sectioned crossmember. I don't think anything will change as far as engine placement, though. Just doing it for ground clearance.

[TopFuel1966]

Originally Posted by Jonboy

Brew, the rails are similar, I think. I didn't want to spring for a set of headers until I knew for sure they wouldn't work. I was looking at the new Hooker cast iron headers, but I will try what I have first. Minor trimming isn't really a problem, but major trimming will be.

Ivorton, the driveshaft should be the same in relation to the truck. If it fit with a long tailshaft TH350, it should work with the 4L60E.

One small deviation I will be doing on mine is a sectioned crossmember. I don't think anything will change as far as engine placement, though. Just doing it for ground clearance.

I used manifolds from an early camaro/firebird LS-1. These are stamped steel so it's easy to cut the big flanges off and replace with smaller ones.

[ivorton74]

@jonboy...u should start a thread when u begin ur swap. i can maybe use ur swap as a reference since ur trucks the same year as mine.
@topfuel...those headers look nice. where'd u get em and what brand are they?

[TopFuel1966]

These manifolds came from the factory on the 98-99 camaro/firebird LS-1. They are stamped steel instead of cast iron so the large header pipe flange that interferes with the frame can be cut off and a standard 2 1/2" flange can be welded on in its place.

[ivorton74]

That sounds like a good idea.I think iI'll use the ls1 f body headers then.
btw...if I get a motor with drive by wire how difficult is it to mount the pedal in the truck?
Also I'll want to supercharge it in the future. What's the best supercharger kit out there? I see alotta guys using procharger.

[pwtr02ss]

Originally Posted by ivorton74

I want to do this swap in the future and im just doin some homework. I have a few questions about the swap especially in these early squarebody c10s.

I just did a 07 5.3 swap on my 74 last year

1. So I'm gonna do a 5.3/4l60e swap.The truck has a 350/th350 combo in it now. the truck is a longbed c10. Will I have to shorten the driveshaft? It has a one piece shaft in it. Also can I use the stock trans crossmember? This will be a budget swap so I dont want to have to get a new crossmember fab'd.

I had to get a longer driveshaft made, it seems to spend on the mounts you buy and whether or not you have a long or short tail shaft. My crossmember stayed in the same place but drive shaft was 3" short.

2. What is the best adapter plates to use? Im trying to choose between dirty dingo and transdapt.

No sure what brand mine are but they worked lol, I bought them from a guy that was going to do a swap then went with a 67-72 instead. They placed my motor pretty far forward.
3. How hard it is to take the harness off the motor? Where's the best place to get the harness redone and ecm ref lashed?

Taking harness off the motor is simple. I sent mine to Current Performance for the conversion and I have HP Tuners so I did my own tuning.

4. Can I use the 74 gas tank with a electric fuel pump or do I have to use one from an 87? How do I set the fuel system up?

I used a 87 tank, 87 sending unit, and a pump from a 97 vortec 350. Wiring it up is simple, one hot that comes with your harness, ground it, and the fuel level wire hooks to your factory one.


5. I want to stick with the original 100MPH speedo instead of the 85MPH speedo from the newer trucks. How do I make this work?

6. Which headers will fit my truck without cutting the frame?

7. Im looking for some cheaper ways to get more power from the 5.3. Any suggestions?

8. Can I use my stock rad or do I need a different one? I read the fboday rads and fans can work.

I just bought a new aluminum replacement for a 74' from rock auto, it comes with the steam port thing on the front. I used camaro electric fans, they fit perfect!

Hope u guys dont think these are too many questions but I need as much info as possible. This will be the first time Im attempting something like this. I may have more questions so bear with me.

This site is full of information but a lot of it you will learn as you go. I have a lot better understanding of what I am reading now that I have done it. It all seems like a lot to take in but its really easier than you think.

[ivorton74]

btw..did u guys upgrade ur brakes and rear end? Im not really sure of the gear ratio in my truck though.

[BR3W CITY]

brakes, yes. I upgraded to Wilood D52's from a vendor, for the front. Rear is still drum on a 12bolt, 3:73's

you mentioned supercharging. For the truck setup ls motors, procharger seeems to have market share and is the primary centrifical used. If you want a roots/screw (there is a difference but i don't remember it) Magnacharger, and whipple have setups, and edelbrock has some but iirc nothing for the truck intake.

[Jonboy]

Originally Posted by ivorton74

@jonboy...u should start a thread when u begin ur swap. i can maybe use ur swap as a reference since ur trucks the same year as mine.

Ivorton, I have a build thread, but I am pretty lazy during the summer. Here is a link: http://67-72chevytrucks.com/vboard/s...d.php?t=433689 . Hopefully it will cool off soon and I can dive in.

In the rear, you should have a 12 bolt. That shouldn't be a problem, as long as everything is in decent shape, and you like the ratio. Mine has a 3.73 in it, so that'll do for me. The brakes are stock for now.

[ivorton74]

@jonboy..damn man u got a beautiful truck.i wish mine could look like that. just bloody awesome bro. btw how do u take off the front clip of the truck?

[Jonboy]

I took the hood off, then removed it as a unit with help from a buddy. Thanks to living with a HOA, I split it up and put it in my backyard after that. Thanks for the props, though. The truck stays in the garage, and my wife's car sits outside. It's not the most popular move, but there are some priorities.

[ivorton74]

how many bolts are there to take out to remove the clip? i looked on my truck today and seen two at the back of the fenders by the hood hinge.

[Jonboy]

There are 4 bolts at the hood, two that hold the core support to the frame, and three at the rear of each fender (two up high, one from the inside at the bottom). A 9/16 will work on everything but the core support bolts. You will need to remove the grille to access those as well.

[ivorton74]

btw what did u guys use for fuel lines?