C4 Corvette LS Swap Project


I picked up a 1984 Corvette from Steve at Turner’s over a year ago now. Body and frame are spotless, but the interior needs some elbow grease, and there is a rod that is tired of being stuck in the dark and wants out. Perfect candidate for an aluminum block 5.3LS + T56 swap. Plan is to pull the old engine and tranny out and get it ready for the new powertrain to go in hopefully this summer.

Engine will be managed with a GM truck ECU wired stand alone from the chassis wiring, I’m sure MikefromUSA will get his fingers on it as well, haha.

I’m pretty excited, should be a fun project, and finally a project that will net some actual power, lol


That rod is really angry…

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Swung through the Southern Tier on my way back up from DC and picked up a wiring harness. 03 Trailblazer EXT drive by wire harness, which will allow me to maintain cruise control with the new engine digitally, so I can get rid of the original massive vacuum cruise control. Once I have the engine to match I’ll be modifying it myself, and probably doing a wire tuck. One of the O2 sensor connectors is broken, so I haggled them down, but I’m just going to steal the good connector off a spare drive by cable harness Dad has.

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Found me some GTP injectors that were already cleaned and flow tested on Ebay, and they flow a little more than the stock LS1 injectors so I can run a shorter duty cycle NA. Leaves me more of a ceiling on the fuel system.

Also picked up an LS1 intake manifold tonight from scotts94_z28, low mileage and should get me up and running with the stock hood.


you do you.



Finally going to get this build going again. Picked up an all aluminum 5.3L LM4 with 101,000 miles.

And got it on the engine stand tonight, going to do some cleaning up on it and trying to get it fired up on the stand before I put a lot of time into it. Now the search for parts begins…

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Made some progress this weekend. Pulled the engine harness I’ve had for about a year out and started stripping insulation in preparation for removing everything I don’t need and tucking the harness

It beat the shit out of my hands

Also pulled a relay and fuse panel out of a 97 Chevy truck over the weekend to use as the engine relay box. Little overkill but it allows for expansion.

Last thing I accomplished was laying the harness over the engine and plugging everything in. That way I can label all my connectors before I start tearing into things, and I want to fire it up on the engine stand before I start modifying things.


Cool build bro


Is this thing in that car yet?

I want to see it. Should be a pretty nice cruiser. Full on 80s glory but more than 125 hp lol


nice. I basically have the same motor in my c10 except mine is the L33

either way should def be better than what that crapper came with!



Not yet, haha, I’m tempted to try to get the original digital gauges working, but I have a set of Auto meter Pro Comps sitting around that would be perfect for it.

Just going to an aluminum engine is going to save about 150 lbs out of the front end, should get me to right about 3000 lbs less driver, that and 300 hp will be very fun. Maybe more some day.


Going to do any style upgrades? Jordache Jeans perhaps?


Already working on the mullet, acid wash jeans are on back order.





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im going to be ordering a tsp 224r for my truck soon so if you want the l33 cam let me know


slap a cam and springs in it, you will love that combo. Will the T56 fit without major tunnel bashing?

There are a few of these builds floating around on LS1Tech, keep the updates coming


They came with 6 and 7 speeds from the factory so I’m guessing the t56 will be ok.

The dana rear end has many options and is already strong.


needs a rear mount


no it doesn’t… (ask me how I know)

Nice build. C4’s are usually picked on, but in the right hands can turn out purty nice.


Yeah no window louvers… Lol

Thanks for the offer, probably going to be next year before I start modifying the engine for more power though.

Planning to do just that once I get everything ironed out in the initial swap. Yeah the T56 will fit, just need to build a custom tail mount to mesh with the ladder bar that connects to the rear end. No transmission to body mounts in these, the whole drive train is suspended from the engine and rear diff mounts. Kind of a first generation torque tube.

It actual has the 4+3 in it now, which is more of a longer transmission than it is a big transmission because of the overdrive bolted to the back ofif it. The 6 speed optional ZF transmission is huge though.

Unfortunately this is the only year the manual transmission cars came with a Dana 36 instead of a 44. Ok at 300hp and not beating on it, but what fun is that?

Nah, still not sure if I’ll pro charge or just go NA, no room for a supercharger under the stock clamshell and the aftermarket cowl hoods look terrible.

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All that suspension technology in a nice light car, ruined by last minute emissions laws.


Any reason you would do this and not just buy a C5? You can find high milage C5s for fairly cheap now seems like a wash on any savings by the time you add everything up.


id be willing to bet he picked this up pretty damn cheap

a few months ago I was looking for a c5 to beat on daily and the cheapest I could find one was about 9k.
running and driving c4 chassis cars were 4-6k all day long…


Yeah this is going to be running with double the stock horsepower for $5-6k.


all the “cheap” C5s (7-9K) have been driven to hell and back, beat up, hack job modified…they need another 2-3K in work right off the bat. Plus automatic C5 coupe’s suck


Is the digital dash going to function after the swap?