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I have a LM7, 4L60E Tranny, and a NP241C. I want to mockup the Engine fit to install engine mounts. I would like to make sure I have good clearance for the headers and I am looking for recommendations. I know nothing about headers. The truck had a 350 with shorties so I assume that is the low fit risk way to go but I have no clue on brand and model number. Thanks

I am not sure what you are asking for recommendations for. Motor mount adapters? Exhaust manifolds/headers?

Well, I think you need to hang motor,trans,transfer case to get an idea how to mount and will have to fab crossmember, engine mounts to get it set in frame. Then figure out exhaust. I lot of trial to fit everything, Im a carpenter by trade so what do I know. My truck took 3 years of Sundays, but I went the easy way, frame swap.

If you haven't already, check out Barnfind49. He did a very clean LS conversion with ac. He did use the original transmission but tons of good info/reading. Also, search LS info from coilover. Evan's shop has completed many LS conversions. Evan isn't with us anymore but luckily we can still tap into his wisdom via search.

Good Luck, RonR

The front output on the your transfer case is on the driver's side, front drive axle has carrier on passenger side. What is your plan to deal with that?

Just out of curiosity, what will the LS do that the SBC-the single most aftermarket supported engine in the world-will not? Coil pack ignition and sequential multi-port EFI are easily achievable on an SBC; power steering, air conditioning, aluminum cylinder heads, single belt serpentine drive are super commonly available also.

If the rig already had a 350 in it, it's pretty trivial these days to get 400+HP and lbs/ft out of a very streetable SBC build, for a lot less time and money versus the shoeorn and greased 2x4 approach of LS adaption. Nothing against the LS, I get it's a more modern design. I also don't mean to cast aspersions on anyone doing this swap either, I just don't understand in this case. Because what's there to begin with can be made to work so well in the modern sense-power, mileaage, reliability.

I put a Cadillac V8 into my school bus, so I'm not coming at this as a stranger to putting a strange engine where it wasn't designed to be :-) In my case I just needed a lot of torque at low RPM, and I already had a yard full of buildable cores.

Stock LS stuff has everything you just mentioned that people upgrade on a SBC. Plus better sealing, longevity, and a pretty darn perfect EFI and ignition system that has 5000x the engineering than any aftermarket parts available. The worst stock LS heads still out flow a good set of SBC heads and they cost nothing. I have NEVER paid more than $500 for a running 4.8/5.3/6.0 in anything I ever built and I actually have all 3 sitting in front of me in running and driving cars/trucks. So for $500 I get complete fully dressed engine, harness, ECU and MAF. That has a perfected EFI and ignition that supports pretty much whatever I throw at it and starts and runs reliably getting mid 20’s MPG and not leaking oil. Nice serpentine system with automatic tensioning. A beautiful reverse flow cooling setup with a factory high flow pump, no coolant in the intake, a factory intake that is absolutely hands down better than any aftermarket parts ever produced. Then if your swinging for the fences making power (me in some applications) there are the 6 bolt mains and the great oiling system that sits under the front cover not hanging down low in the pan. The valvetrain in a LS is also pretty darn good and tough in stock form aside from the AFM engines but I stick to the older stuff so thats never a issue. Im sure Im forgetting things but thats off top of my head. Dont get me wrong I love old engines but the LS stuff is just like plug and play upgrade success in my eyes.

OK, all that sounds fair enough. I never found the SBC to be more prone to leak oil versus anything else, and all that 'perfected' LS stuff came from the previous small block Chevy programs. HEI ignition runs without trauma or even.. maintenance ..for decades. I've seen aftermarket parts vendors fix more than one factory foible over the years (not related to any one specific engine, mind you) so I don't buy the "5000x more engineering" than any aftermarket parts, line of reasoning. The LS hasn't been around as long as the entire world has been making stuff for the small block. I feel like it's a pretty well sorted out unit, at this point.

I guess it's a 'buy once, cry once' deal after you get past the initial expense of the swap... No LS swap guy has ever admitted to paying more than $500 bucks for an LS, so I decided to run down this mythical cheap powerplant. This was the reasonable option for a new one: https://www.speedwaymotors.com/LS-Gen-III-6-0L-Crate-Engine-Kit-364HP-450TQ-Trans-Control,586516.html?utm_matchtype={match_type}&msclkid=20582cb0a6f213fba97a451625b42f42 Over nine grand, and that doesn't include ECU, exhaust, fuel, ignition, etc. that you'd need.

Well that is pretty far from $500, but it looks like I could get a warranted used one starting at $2200 from these guys.. https://603autosalvage.com/used-6-0-ls-engine-for-sale/ Which seems a lot better, however they don't mention if that includes the ECU and wiring, however it might or might not include the intake, fuel rails, and maybe the accessory drive.

For those interested in doing this swap (including myself, since 'LS for Everything' seems to be a thing these days) the 603 Auto Salvage website paints an accurate picture.. You aren't gonna spend $500 and have an LS rig in two weekends. It's not a trivial swap operation-far more complex than my Cadi V8 engine swap, and that was a pretty straight, old GM to old GM switch up. Of course, back then there was almost nothing available pre-made to do what I did, so I had to make every expensive mistake I could make along the way..

But anyway.. to answer the OP's question about exhaust manifolds for an LS into '60-66 Chevy truck, you can buy them here for $400: https://www.lmctruck.com/mechanical/engine-swap-parts/cbe-1960-66-ls-series-swap-exhaust-manifolds. I'd go cast iron whenever possible versus headers. Longer life, fewer leaks, won't rust out. The above mentioned units also support up to 500HP.

Continuing down tonight's ADHD rabbit hole.. Holley offers a whole bunch of.. all you'll need to stick an LS into the ole' 60-66: https://www.holley.com/platform/chevrolet/c10-pickup/1960-1966/engine/ls-swap/ It won't be $500.. but it will bolt in, and someone's already done the homework for us :-) Shewwwt, I'm kinda selling myself on this plan! Well, except for the part where I don't have the money, and 417lbs/ft at 4100 RPM just isn't the same as 550lbs/ft of 500cid Cadillac V8 twist at 2600 RPM, in a 15,000lb school bus.

So I guess it comes down the the old adage.. money, time, skills. If you've got the money, you can get it done pretty fast. If you don't have the money, you could take more time and find that unicorn $500 6.0L LS out of a wrecked pickup, and in come the skills to build all the brackets and mounts and adaptions yourself. Super rewarding.. but plan on the above mentioned three years of Sundays before your first night out in it. :-) It sounds like a great idea, but after the engine you'll probably want a more modern gearbox behind it, so there's that to consider.

Why buy a engine for $500? Just go buy a rotted in half silverado for same or less or even free. Thats not a unicorn that’s commonplace around here. Then you have pretty much everything and then some to get going. My 4.8 engine i bought Complete in a truck for like $300. I scrapped the cats and sold the trans and it paid for itself. That engine had 200k on it and ran like a absolute top. It ended up making 535hp/600tq with some boost and a set of valve springs. Stock everything else. Oh and that was put through a saginaw 4 speed that everyone called “junk” hahahahahhaha. I swear we live in a constant cycle of old guys repeating the same dumb things that they heard from some guy that new a guy that said his uncles didn’t work but they never actually did anything themselves.

I can in fact LS swap things in a weekend or 2. Its been done with planning and having parts hanging around to test or modify.
I pulled the old flathead V8 out of my ‘41 ford truck and had a LS permanently mounted in place and wired ready to fire in a few weekends. While working a full time 40hr job. No its not gonna do itself. Gotta put the work in.

Sadly, wrecked Silverados with perfect LS drivetrains aren't $300 around here. And yeah-you've now done several LS swaps so of course you can do it in two weeks, for $500. Keep in mind, not everyone can.

If I had another bus like mine and wanted to put a Cadi V8 into it, I could also now get it done in a couple weekends-because I made all the expensive mistakes the first time so now I know.

But anyway.. never have I said it couldn't be done or wouldn't work or was even a bad idea. Just don't wanna blow smoke and tell some rookie who's never done an engine swap before that he's gonna drop $500 and be up and running in a couple weekends. That's not really a fair expectation, even if they just go buy all the stuff I linked to above, which makes it easier.

Yup i could build my truck over again and use only specialty swap type parts from a magazine and not think outside the box or just want it all to “bolt together” and probably spend another 5k easily. I do wish they made muncie 319 gear shift rods for LS swap because those were a lot of trial and error to get right!

I just looked for fun on marketplace. $350 for a complete perfect running 5.3 dropout engine. Add fuel pressure and hook up some wires and your ready to rock.

Throttle linkage? Exhaust? Engine mounts? Transmission bellhousing/flywheel/clutch? If automatic, then shifter controls? How about the vastly upgraded fuel system necessary to feed a modern fuel injected power plant? Engine gauges? PCM tuning to account for vastly different new operating environment, VATS delete, etc.?

The end result will be great. Not denying that at all. Just saying, get ready to put in the work-because "fuel pressure and some wires" is truly the tip of the iceberg.

When I did the Cadi swap into my bus, I got lucky in several ways. First, the height from the rear face of the block to the crank flange happened to be the same between SBC and Cad. So after I had the flywheel machined to fit the Cadi crank, it sat the same distance from the factory flat adapter plate which mated SBC to round bellhousing. I was able to retain the factory heavy duty starter from the 327, bolted into the bellhousing. Was also able to simply drill the different BOPC upper holes in that metal plate and with a few judicious bolts and nuts, the Cadi bellhousing bolts are all occupied. Also I was lucky to have the hydraulic clutch option so no Z bar business. I got the heavy flat steel motor mount plates from MTS (Cadillac hop up parts purveyor Larry Kruzick, this was 1994 after all) and simply cut the bolted on factory engine mounting ears down. Moving them forward to the six cylinder holes in the frame, made 'em center perfectly with the more forward coordinated corporate mounts on the Cadi engine. Then neighbor welded on the plates after I fit the engine in. I had to make the throttle linkage, adapt various cooling fan system arrangements.. I actually ended up moving the whole engine and transmission assembly forward two inches, decades later in 2021. Had to have a longer front driveshaft segment made, but it then made the drivers side cylinder bank clear the firewall so much better, I wish I'd done it back in the '90s!!

Seems so simple now, but that was a lot of weekends back then, when I'd never done anything like it before (despite being a mechanic by trade) and there was sadly not a Stovebolt forum yet to help me. Just me and my Dad. I miss my Dad.

If someone had never done an engine swap before, I wouldn't advise them to expect it driving in less than a summer of weekends. And that's if things go pretty well. Just take your time and enjoy it :-)

Tronman I think this post has went way sideways from the OP questions. He had a truck with a SBC. He has a LS with trans attached. So it just bolts in place. He was asking about headers that fit. I awnsered your question about SBC vs LS then the thread went down a totally different rabbit hole.

To answer your last questions about “vastly” upgraded fuek system…. My truck (1949) uses a gravity feed tank which I added a frame mounted electric pump and a line to the fuel rail. Done!
As for gauges….they gauge things. Screw in the sender from SBC into a LS. Find a spot that works. A bushing adapter is a few bucks if needed. Mechanical gauges like mine all work fine.
Im not sure what you meant by operating in vastly different environment……the engine in my 49 has no idea its not still in a silverado from early 2000’s. There really is no tuning required to make it run any differently. Yes Vats needs to be turned off and if you run a check engine light and want it off you can check a few boxes to ignore in the software for factory ecu. These LS engines ARE ANTIQUES. They are in some cases 27yrs old and the technology is super basic honestly. They dont care about much. You can disconnect all 02’s, disconnect MAF, disconnect cam sensor or any sensor besides crank and map and it will fire up and run happily although fuel trims wont be active it will still run down the road just fine.

So.. all the expense and time to put in the LS with the advanced engine management which is much of the reason to get away from the SBC.. then run it in open loop (no MAF or O2 sensors)? Sounds great.

And no it doesn't just 'bolt in place.' If it did, then there wouldn't be all the pre-made mount and crossmember adaptions that I posted, so a guy can avoid making them himself. I also posted links to the iron headers you can buy, in answer to OP's questions. From those, to a working link for a site where you could buy the warranted used engine, with a realistic appraisal of what's involved in the swap, I brought receipts-versus "I've never paid more than $500 for an LS" and "I have three of them right here" and "I put one in my '49 in two weekends."

All I'm saying is that not everyone is the LS master that you are, and us mere mortals are going to require more than two weekends and tuning software to make it work. Again: agreed-LS swap is a good idea for going the modern way. As I also said before "Shewwwt, you're even selling me on this plan.." my point is merely to be honest-it takes some work to get it done right, and it's not fair to a would-be first time engine swapper to paint an unduly rosy picture of how it's all just gonna bolt together in a snap. That's what I'm saying.

I converted a 72yr old guy from a 400 sbc to a Turbo LS. He did a nice job working on it on the weekends when he could. He only had me help him on the harness and a few random questions about turbo related stuff. Even when he was done and running around in his almost 700hp street truck he was like “darn that was easy I cant belive I waited this long and listened to all these guys scared of newer technology that’s actually simple”. He drives around and does rolling burnouts starting from the speed limit. On the flip side of the coin my younger farm kid friend with limited wrenching skill or experience did a swap and worked even harder and spent even more $$$ to run a carb setup and he swapped a squarebody in a 3 day period. He made his own plate and bolted stock sbc clamshell mounts to his because he wouldn’t dare spend $25 on something he could make from scrap.

Gents - Seems about time to drop a reminder that we need to get back to letting the OP read through/catch up with the offered information. He hasn't been back since late February, so hasn't even seen the last 10 replies, much less responded to the info after his first post. Let's give him a chance to come back and let us know if he has enough info or needs more details please and thanks.

Otherwise, this horse has been beaten on enough and if you want to continue the conversation between yourselves, feel free to do that in a PM.

Gdads51, fwiw, I’ve REALLY enjoyed this back and forth between Tronman and Barnfind. I’ve been on the SBC/LS fence for a long time….I love reading about this stuff. I’m an “old guy” still running a SBC 327 (w GM TBI!) in my ‘48. It’s all dialed in so why should I change? If it ain’t broke, don’t fix it. Both of you guys make a lot of sense and I can’t be critical of the logic from either camp. If I do, however, build something new, it would be a no brainer to go LS. Thanks guys, keep up the good work!

Flatblue4748 -Thanks for the feedback and agree that the back and forth has provided an incredible amount of information. Not trying to rain on anyone's parade and apologize if that's how it came across.

My only point was to suggest it may be time to let "Gary Smith" catch up and come back with further questions or what his decision/plans might be so folks can continue to offer any needed help.

A good point. I've learned a lot here, too. While researching the options for an LS swap, I get the impression that the '60-66 are among the easier platforms to do so. Also, looks like there is now a lot of bolt-on support for this swap nowadays. Just to be clear: I'm not afraid of new tech. But I won't discount the old engine's potential, either. Finally, I'll admit: I'm lazy! If the rig came with an SBC from the factory, and it will do what I want (pull something, as opposed to burnouts at freeway speeds) then I'll just let those factory bolt holes line up and really be done with it in a Sunday afternoon.

Back in the '90s when I did the Cadi V8 swap, MTS was all 'Just buy my mount kit, then my adapter plate, you can do this in a weekend-it's so easy!!' Yeah.. not so much. I did it, and it turns out that the 500cid Cadillac V8 is a very good engine for shifting 15,000lbs of school bus fast enough to keep up with traffic. Would I do it again today? Or would I find a bigger LS with a six speed Allison behind it, then lock the 2 speed rear end in High and send it? Or just buy a modern Eaton rear axle? The answer isn't so clear cut anymore, with these more modern options which are, apparently, just one insurance settlement wrecked Silverado away from reality.. and don't forget the Duramax option.

GREAT thread, lot's of info to digest for sure.

Copart, a major seller of insurance (and other) damaged vehicles. Bargains to be had. This link shows current listings with auction close dates of trucks that have LS engines (many vehicles shown aren't up for auction yet).

One thing to remember (and learn about), third parties are available to help with purchase if one doesn't have a dealers license or friend that does.

RonR