# LS swap questions



## Duff (Jan 12, 2020)

I've been mulling over engine choices and ideas for my 66 GTO project car for awhile, and I've checked the average prices on a Pontiac and BBC strokers, but haven't considered an LS swap until now. Since I know zero about doing such a swap, I have some questions. What size engine should I be looking at? Donor car or new crate? What manual transmission? Who make the best install kit? Will I have to modify the trans tunnel? Thanks!


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## 67ventwindow (Mar 3, 2020)

How much power are you looking for? Are you looking to upgrade the rear as well? LS Classics makes some retro looking EFI intakes for the LS3. Would have to fab a RA pan then you would have something. I am looking to get aT56 magnum to sit behind my 389 but would like to know if the 389 goes south would a LS install relocate the trans. I just now started looking at that. Will probably have better luck on a LS forum.


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## armyadarkness (Dec 7, 2020)

IMO, when you compare parts, there's never really any money to be saved. 

8 months ago I started out researching a manual conversion for my car. I wanted to go Muncie 4 speed, but despite everyone arguing my findings, the Muncie was just as expensive as the Tremec. Plus, the Muncies are all 40 years old and rebuilt, vs brand new, and they dont have overdrive.

So if youre trying to save money, then it's not going to work... An LS swap is going to require so many little additional items that you're going to fly right past any budget. Unless you buy an LS setup from a wrecked SIlverado and take all of the parts, but that's a very popular item these days. There are definitely ways to save money, but in the end, they all require a lot more work and the savings arent usually large enough to make them worth it.


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## Jared (Apr 19, 2013)

It really depends on how far you want to go with this. Do you want something that just runs good or a show car when you pop the hood? A junkyard swap will run good but it will basically look like a junkyard swap. If you go that route stay away from any used engine that has AFM. These engines are prone to cam shaft failure at low mileage even when maintained properly. I had a 5.3 in my last truck that failed at 85K. A show finish LS swap will cost you more than a Pontiac build by the time you're done. BBC will also probably cost more when you factor in all of parts that are not interchangeable between the Pontiac engine and a Chevy.

There really isn't much support for the LS swap on this forum but it does show up on occasion. Most here are running Pontiac engines.


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## Noangelbuddy (Dec 6, 2017)

67ventwindow said:


> How much power are you looking for? Are you looking to upgrade the rear as well? LS Classics makes some retro looking EFI intakes for the LS3. Would have to fab a RA pan then you would have something. I am looking to get aT56 magnum to sit behind my 389 but would like to know if the 389 goes south would a LS install relocate the trans. I just now started looking at that. Will probably have better luck on a LS forum.


I put a T56 Magnum in my 65 GTO. It was much larger than my original four speed. It came with a template as a guide for cutting away tunnel sheet metal to enable it to fit. For a change , I was meticulous about reading the instructions before making any cuts. I found the template inadequate. It indicated I needed to cut away metal toward the rear that did not need to be cut. The floor pan had a roll bent into it for strength (my assumption), which I did not want to cut out and possibly cause other problems. In my case I needed to cut out more toward the front than the rear. The template suggested the opposite.

I purchased a kit with the transmission, which included all fluids, the template, sheet metal for new larger tunnel, transmission support member and new driveshaft. The Magnum came with instructions to boresight align the bell housing for warranty purposes (at least that is what my kit asserted; since they became the middle man between me and Tremec). It was necessary to ensure correct alignment between the bellhousing and the crankshaft. Not hard, but not intuitive and you will have to buy some inexpensive HF tools to accomplish. Having to do alignment was news to me, I thought if the bolts lined up you were good to go. Be sure to do tons of research. Good luck on LS forum and get your wallet ready if you make that swap.

Sorry for being long winded, but how much you read and how much you heed is your call. Best of luck with your Magnum.


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## 67ventwindow (Mar 3, 2020)

Noangelbuddy said:


> I put a T56 Magnum in my 65 GTO. It was much larger than my original four speed. It came with a template as a guide for cutting away tunnel sheet metal to enable it to fit. For a change , I was meticulous about reading the instructions before making any cuts. I found the template inadequate. It indicated I needed to cut away metal toward the rear that did not need to be cut. The floor pan had a roll bent into it for strength (my assumption), which I did not want to cut out and possibly cause other problems. In my case I needed to cut out more toward the front than the rear. The template suggested the opposite.
> 
> I purchased a kit with the transmission, which included all fluids, the template, sheet metal for new larger tunnel, transmission support member and new driveshaft. The Magnum came with instructions to boresight align the bell housing for warranty purposes (at least that is what my kit asserted; since they became the middle man between me and Tremec). It was necessary to ensure correct alignment between the bellhousing and the crankshaft. Not hard, but not intuitive and you will have to buy some inexpensive HF tools to accomplish. Having to do alignment was news to me, I thought if the bolts lined up you were good to go. Be sure to do tons of research. Good luck on LS forum and get your wallet ready if you make that swap.
> 
> Sorry for being long winded, but how much you read and how much you heed is your call. Best of luck with your Magnum.


 Not long winded. You say sheet metal most of them say its a patch for the tunnel. Is there allot of work to make it fit? I have read through a few of the instruction manuals for these kits. I saw somewhere about aligning the bell up. The good thing or bad thing. The engine and tranmission were dropped in last year so there shouldn't be any stubborn bolts. I have a spare Pontiac motor that I can practice the alignment on prior to install week. I need to get the car back in the garage and make sure there isnt any gremlins hiding, Before I order the kit this winter. This is a sheet metal winter so if you dont hear from me Im stuck in the trunk.


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## Duff (Jan 12, 2020)

67ventwindow said:


> Not long winded. You say sheet metal most of them say its a patch for the tunnel. Is there allot of work to make it fit? I have read through a few of the instruction manuals for these kits. I saw somewhere about aligning the bell up. The good thing or bad thing. The engine and tranmission were dropped in last year so there shouldn't be any stubborn bolts. I have a spare Pontiac motor that I can practice the alignment on prior to install week. I need to get the car back in the garage and make sure there isnt any gremlins hiding, Before I order the kit this winter. This is a sheet metal winter so if you dont hear from me Im stuck in the trunk.
> Awhile back we attended Cruisin the Coast as spectators, there were a ton of car classic / muscle cars with LS swaps, most were very clean installs, sounded great and judging from the burnouts, I'd say they had plenty of power. I do think the late model engines look out of place in a muscle car, but if there's no permanent mods, then I could live with it. I've done a BBC in GTO before, mounts, bell housing and headers is just about all you need, pretty straight forward. Originally, my car was a 389 tri power 4 speed with no comfort options, original engine is gone, but I do have the restored / modified tri power, M20 and a 67 chevelle 3:31 12 bolt, so I have a good start on Pontiac build. If I went the Pontiac route, I'd have Butler do the build, and last I checked they weren't taking any new orders, but that'll change in time. I'll head over to an LS forum and see what donor cars I should be looking for. Thanks for the replies.


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## GTO44 (Apr 11, 2016)

All comes down to budget. If you have a nice budget, go brand new with a warranty…









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If you’re on a budget pretty much any iron block will fit the bill. The most common “ls swaps” that are sourced motors from the junk yard / craigslist / LQK type of place would be your iron block 6.0’s and iron block 5.3’s. Shoot for a gen 4 block if possible. They will start in the 330-350hp range. Both will make great power with a cam, intake and set of headers. You can also find a set of used 706 heads for $200 on craisglist. They have slightly smaller valves but also smaller combustion chambers which will give you more compression and actually make more power than the other bigger valved heads.

Keep in mind those are actually “Vortec” motors. The only “REAL” LS’s out there are the aluminum block variants… LS1, LS2, LS3, LS6, LS7, LS9, and LSA. Obviously the true LS aluminum blocks will be harder to find and more expensive. The perfect find would be a 400hp LS2 from an ‘05-06 gto or 05-08 base model vette. Having a true LS will help resale value down the road. And the LS2 is cheaper than the LS3 and better name recognition than the Ls1. The LS1 from a 4th gen camaro/TA, 04 gto and 98-2004 corvette is a great option as well. And of course if you can find a crashed out 2013+ LS3 from an SS camaro, thats going to be your best most powerful option. Starting off with 430hp.

You can also source an LS2 and do an LS3 top end swap for pretty cheap… stock ls3 intake, stock ls3 heads and a stage 3+ BTR or TSP cam with headers will get you 450-475rwhp (around 550crank hp).

For transmissions again it comes down to budget. You can get the holy grail of gm 6 speeds, the TR-6060 that came with the factory LS3’s in late model camaro’s or the highly regarded T-56 like the late model gto or 4th gen camaro’s and TA’s. Both are big and as mentioned above usually require trans tunnel cutting of some sort. We have switched to using the brand new TKX 5 speed transmissions from tremec. They replaced the TKO500 and TKO600 variants. They are small enough to fit in almost any car with no fabrication. They were made specifially as an aftermarket solution from manual transmission swaps. Most people with older hotrods are jumping on board. Infact today, We just received a brand new TKX with a full install kit for a ‘68 mustang fastback. Its a beautiful piece. Handles 600rwhp. Shifts smooth. Reinforced case. Choice of 10 spline or 26 spline. Choice of gear ratios. Choice to run hydraulic or cable operated clutch. And its very reasonably priced. We order ours from Silver Sport Transmission. Having a shop being I got a 10% discount. (Pic attached)

For engine management you can get a GM control pack for around $1500. A little more if you have an LS3 with drive-by-wire. We usually skip that and go right to a Holley Terminator X. Makes install easier, tuning easier, adding sensors easier plus you can control boost, nitrous, 2 step, 3 step, and pretty much anything else you wanna do. The factory control packs work well on a stock motor if you arent adding a bunch of go fast parts. Any time you change the stock setup the ECU will need to be tuned… And tuners now a days are getting $700-800 for a standard dyno tune. For $1200 you can get a terminator x and let the self learing do its thing.


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## Duff (Jan 12, 2020)

Now that's what I'm talking about! Thanks for posting that information, it gives me a good starting point and will really help me make the decision. Thanks, again Duff


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## armyadarkness (Dec 7, 2020)

I have converted many over to manuals. The tunnel fab is a few hours of work. No big deal if your metal is clean


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## Noangelbuddy (Dec 6, 2017)

67ventwindow said:


> Not long winded. You say sheet metal most of them say its a patch for the tunnel. Is there allot of work to make it fit? I have read through a few of the instruction manuals for these kits. I saw somewhere about aligning the bell up. The good thing or bad thing. The engine and tranmission were dropped in last year so there shouldn't be any stubborn bolts. I have a spare Pontiac motor that I can practice the alignment on prior to install week. I need to get the car back in the garage and make sure there isnt any gremlins hiding, Before I order the kit this winter. This is a sheet metal winter so if you dont hear from me Im stuck in the trunk.


Not too much work. Let me clarify on the sheet metal. Mine came as a flat ”shaped” single sheet. Wider at the top, narrower toward the rear. There were several cuts from the outside edge inward to assist you in bending the metal to eventually form a tunnel patch. There was also a paper template intended to help you transfer marks for more cut and bend lines on the sheet. When I did my tunnel fabrication patch I was still learning MIG and I cheated with a few sheet metal screws. Came out okay, got covered with carpeting and the center console topside. From the bottom I sealed and coated the metal with POR15. Probably overkill since car won’t see snow, ice or rain. Will add photo if I can find one.


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## armyadarkness (Dec 7, 2020)

Most of the ones that I've done gave you dimensions for fabbing a tunnel mod.


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## Duff (Jan 12, 2020)

I've been looking around on the web, I like this from Scoggin & Dickey, # CPSLS427T56, I don't think the price is out of line, considering it's a new performance engine, not a rebuilt, it's also available in connect and cruise pkg.


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## Noangelbuddy (Dec 6, 2017)

Impressive performance numbers, but that is a costly package. I hope your rear can handle that amount of torque. I looked hard at an LS before I did my swap. The LS appearance did not impress me personally. It lacked bling. Your build, your choice; to each his own. Best of luck whatever path you take.


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## PontiacJim (Dec 29, 2012)

Read this article. It is a Chevelle swap, but you can get an idea of all the parts needed for the swap. Lot of extra parts/money, its not just about the engine.






LS Swap Chevelle Guide


Learn about performing an LS Swap in a 1972 Chevelle in this tech article. We'll discuss lessons learned from our Chevelle engine swap using a 500-horse 6.0.




www.speedwaymotors.com


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