My 14 year old son was given a 80 C3 as a project car. Needs a motor and transmission! My question is I have a 5.3 motor and transmission out of an 03 Tahoe. I know the transmission won’t work but can I use the motor and intake in the Corvette or do I just need to go with a crate motor or find an LS and do the LS swap on it

 

Welcome to the CF!

 

Moved to C3 Tech.

 

I think you can make it fit. It's an LS-based engine, just heavy and tuned for low-end torque. I don't know for sure that the transmission wouldn't work, either, though you may have to make room in the transmission tunnel (even if it's a 4WD transmission, you can convert that back). At one point I looked at an LQ9 swap (with 4WD auto) from a wrecked Sierra 2500HD. It belonged to a local garage, and though interested, they ended up putting it into another truck of theirs.

FWIW, a lot of the recent posts on the "Show me your engines" thread have been of LS conversions. If you search for the corresponding build threads, you may get some ideas about what works for the intake.

 

5.3 ls engine should fit fine. I'm assuming the trans is a 4l60 auto so it should be fine. I put an ls3 with a 4l70 in my 79. There's a handful of ls swapped c3s and decent info out there on what problems you might have to work around.

here's my swap threadhttps://www.corvetteforum.com/forums...-auto-air.html

 

You CAN do it but you need to decide if that is worth the work to complete the swap. A gen 1 small block will bolt right in place but an LS swap is much more involved.

 

OP

As said, 5.3L is an LS.

Did the project vette have an auto or manual trans ?

Is your Tahoe's 5.3L an aluminum block flex-fuel rpo L59, or an iron block LM7 ... or otherwise ?

Trans is surely 4L60E ... but is it from 2WD or 4WD Tahoe?

Do you have the OE LS ECM computer & harness ?

Do y'all plan to use the OE LS fuel injection & ignition systems ?

 

The fact that you asked this question implies that you have not done an LS swap before... Be aware that a swap like this is not for the faint-of-heart or for a beginner mechanic - it's a significant level of effort with a significant level of difficulty.

The Vortec 5.3 is an LS-based engine, so you are doing an LS swap by using it. The LS does not "bolt into" the C3 Vette, and requires modifications to engine mounts, fuel system, driveline, transmission supports, and cooling system. Additionally, you're going to have to figure out the ECM hookups with exhaust ox sensor installation and other systems to keep the ECM happy. The level of frustration to make it all work may doom the project to failure, unless you have good background in fabrication work and custom engine swaps. And it won't be cheap, even though you have an existing engine.

If I were you, and to keep the project "do-able" and "achievable" for your 14 year old, I'd find a complete Gen 1 350 engine/tranny combo out of a 76-79 Nova or Camaro. This will provide you with all the parts, accessories, brackets, pulleys, engine mounts, and systems you need to actually complete the project successfully. If you buy just a crate engine, you're still going to be hunting down all the accessories to make it work, which can be painful all in itself, and you'll still need a transmission with all hookups and a converter. If you want to complete the project before the 16th birthday, I'd keep it simple and keep it achievable... You may otherwise be in for a miserable and costly experience.

Lars

 

Well said. To do one right isnt easy at all...many ls swaps out there are plain ol hackjobs, theres always a problem with them you just wont see them posting about it. Heck lots of guys that try EFI on a Gen 1 put a carb back on.
The trick is getting the right combo and not falling prey to "cheay ebay" garbage with low price tags offering big talk and warranties
Gen 1 blocks are everywhere, any 2 bolt main engine will make plenty of reliable power without costing a fortune, the aftermarket is huge.
Lots of youngsters dont know of the gen 1, read forums with their peers screaming "junkard 4.8 200 buck ebay turbo and 1000hp!"
BS...if they do run it wont be for long.
A plain old 350 can go 200k without a problem. Make his first project simple, he will know if he wants to take that next step.

 

The advice given is all very wise and given by those who do know what they are talking about.
Make the project as simple and enjoyable as possible.
It will be something your son will remember his entire life.
Before you put too much money into this project, check the frame and birdcage for rust.
There are numerous threads on where the trouble locations are, how to get to them and how to assess any problems.
Good luck, welcome to the forum

 

yeah after reading more I’m just gonna find a stock 350 and transmission and build it the way I know how! Swap sounds good and all but way more than I have time to take on between now and the time he starts driving. Thanks for all the information it’s been a lot of help and helped make the decision! I like the idea of original muscle car.

 

All the metal is 100% rust free. However I’m gonna have it sandblasted and undercoating sprayed before we put anything back on it! Hopefully doing it that way he want have any problems arise from any of that for a very long time!

 

Find another running 350 from a wrecked or clapped out Vette.
Lars' advice on Nova or Camaro is good but I believe all of the accessories are wrong.....Alt is on the opposite side, long water pump....etc. I know early
Pulleys and brackets are out there if you look. I would stay with stock Corvette components for a lot of reasons...........mostly for ease of belt lookup on the road.
There quite a few Vette salvage yards out there for pulleys and brackets......I was quoted $160 for everything on a 72 Chevy pickup as they use the same brackets (Water pump and pulley is different as it has a 3/4" shaft in the center.
I would scratch the LS idea myself.......above average skill set is required and a ton of parts will need to be purchased.

Jebby

 

I’m confident I could do the ls swap but it’s a lot more money than I have budgeted and a lot more time also! I’ve talked him into just going back all original! He was given all the original interior but most if not all of the dash pieces are cracked so I’m now having to figure all that’s stuff into the budget as well as motor and transmission! Hopefully we can find and get our hands on everything we need in the next year and a half.

 

Look in this forum classified and you will find 350 engine for sale. It’s mine.