Actually, I was an Electronics Technician for 15 years in the USAF, with an Electrical Engineering Technology degree. Automobile wiring doesn't phase me one bit.

I know what I don't know, and am working every day to reduce the amount of items in the "I don't know" column. That's why I ask questions.

And NO - I don't take your comment as an insult. We Be Good, Derek² :-)

 

Yes I must agree. It is a completely different way of thinking.

However, having done hundreds of engine swaps, and rebuilding many SBC around 20 to 25 years ago, and dealing with every conversion between chassis, engine, ECU, wiring, tuning, etc... I can say that it is all fairly similar. At least, you have a power wire to an ECU, you have the ground to the ECU, then the ECU works. Whether SBC or LS its still 12 and ground. See what I am saying? The engine mount is the engine mount- same thing, different look, shape, design, but it does the same job. Same for alternator, balancer, power steering. Same for intake manifolds, exhaust systems, and so forth. Engines all work the same way. So what is really different? The only difference is familiarity, which is why I agree with your point. If you are unfamiliar with LS then you don't realize how simple the wiring is yet. But that does not make the wiring more complicated- its still a sort of basic, power and ground ordeal.

Tuning wise, you can see both sides. On the LS side, it is difficult to understand and fully tune an engine and transmission especially at 500-1000hp where mods internally must work with electronics for the trans side.
On the other hand, tuning a mechanical transmission is just as difficult if not more difficult. Without electronics the entire pressure coordination system is done via TV cable or some other governing internal fluid force system which depends on proper transmission building in the first place- arguably more difficult than tuning via pressure gauge electronically empirically. So I vote simplicity wins for the LS application with respect to tuning if we are comparing carbs or older ECU configurations from SBC land, LS is far more adjustable and manageable, just not familiar.

Integration can be difficult for other reasons of course. Stuff hitting other stuff. Wrong side things. There is some fab work usually no matter what engine swap. However we must also remember that any custom installation pushing 500+ hp is going to require some kind of custom work whether SBC or LS. Especially forced induction- which is where you want to be BEYOND that power level when running a street setup no matter what type of engine. Making 600+ without forced induction is very easy but the engine config will not be street friendly or mild in any way unless it has some huge displacement and even then, its not going to be economical. Whereas a small displacement LS engine such as 4.8L will do 700 800hp to the tires and still yield reasonable economy and drivability for many years on a stock internal platform. I digress...

The LS has advantages in the ignition system allowing coil over plug and sequential individual cylinder adjust ability which makes diagnosis easier and the plugwires last longer and don't get burnt, its a huge selling point for me over SBC header fingers. This is one of my favorite features, no more burning fingers or fooling with hot plugs. If tuned properly you never look at the plugs for 50k to 80k miles in the LS platform. That is tuning my way. My file is in my sig I posted you can see how I tune the LS engine using HPtuners to look.

Anyways. The point of my post is two things
1. Engine are all similar, doesn't matter 3L 6L SBC or LS, they all use very similar control systems, just modern as the years go up. The early LS from 02-07 has the advantage of very simple electronics, power and ground, tune the ecu, done. no fancy stuff, no direct injection, no active cam movement, no displacement on demand, just start with the simple LS platform and its basically a SBC clone with power and ground minus all the leaking and burning plugwires. I don't think 08+ LS are as simple and probably just avoid those models for swaps into older vehicles. that is why the 02-07 year range is the best LS engine for swaps IMO.
2. The swap can be done simply, but should be researched fully. I want to give confidence but also caution. I advise look at several other LS swaps first to see if you can imagine pulling it off. It is different, but it is similar, nevertheless you need to visualize doing the whole project otherwise it could turn into a slow and stopped effort.

Perhaps the best thing about LS swap is they have already been done done done over and over
LT1swap.com has every wiring pin and a full diagram and how-to wire the simple swap for example.
Ebay probably sells every motor mount or whatever chassis stuff would be needed.
Popular transmission options are still available
and so forth

 

I didn't suggest an LS swap to be glib. And @Kingtal0n has posted a lot more detail.

Right now on Facebook, there are a dozen Tahoes within 20 miles of me that are selling for less than the price of a Sniper EFI conversion kit. All the other stuff you have to do (in-tank pump, lots of electrical, etc), you would still have to do for either solution. For a weekend driver with a desire for a modern, electric automatic, an LS swap makes perfect sense.

If you have a handle on the electrical, at least consider it. There are lots of great threads just in this Forum.

 

LS swap......not interested. I prefer maintaining the original character of the car......not turning it into a C6. If you want a C6.....just buy one. I did.....its nice....but its no C3.

 

For the same price roughly, get the 3.875 crank and make a 421ci

100 more ft pounds torque

mine is 550hp /590ft #

 

and these are all the 400 sbc upgrades that have been taken from that engine and applied to the 350. but the bore is one where you either need to stay with the 400 block or buy aftrmarket.

 

if you buy a 400 from an auto car, it will most likely have the correct balancer. otherwise you need a 2-piece 400 small block flywheel. buying new is highly recommended as the 400 and 454 take the same casting number but are balanced differently and the 400 is far rarer. you can also get a counterweight that bolts between the crank and flywheel to adapt a 350 flywheel, but it is considered bubbaesque... https://www.speedwaymotors.com/1955-...0aAg34EALw_wcB flywheel itself. https://www.jegs.com/i/JEGS/555/6012...aAk3gEALw_wcB# balancer. this pic shows the metal gouged out of the rim to do the external balance. the 350 is one size all the way around. https://www.jegs.com/i/Proform/778/6...waArNSEALw_wcB

 

They were suggesting it to the thread starter tech41.
To many, "maintaining the original character:" would be a stock low power emissions 350 and stock 15" wheels. I think you've already been working in swapping in a suburban 400 engine right? why not buy an old truck :P. Kidding aside, cant the OP draw his own line though?

a c3 with an LS engine is far from a c6 btw

 

Ok....sorry. Sometimes I am stubborn for no reason. Old age syndrome. To the OP....take all the different viewpoints, and decide which one you like.

 

interesting motor.
I can't remember wanting or seeing one.
my ignorance

 

So I'm a big time LS guy. Not a monster HP LS guy but a small to medium HP LS guy. I've done a number of LS swaps over the years with great success.
Having said that I'm kind leaning towards a large inch SBC on my next project. I would not use a old GM 400 block. As I understand the two bolt main webs weren't great back in the day and now they are 40 plus years old? Bored to what over the years to what? Maybe over heated moving the bores around? Maybe decked. Maybe aligned honed? Too many maybes for me.
I was on the Blueprint web site and I was looking at their 396 cube small block. I don't know Blue Print from anyone. Some have great reviews and then some not so much. I was looking at their 396 cube SBC.
I think it would be very cool to dress a big cube SBC to look like a "stock" SBC.

 

Get in contact with cf member DZAUTO, Tom Parsons. You can find him on the "us old geezers" part of the forum (C1/C2). He's as knowledgeable about 400 SBs as anyone else I've seen on the forum and can guide you.

 

So count me in the NOT a big fan of the 400 SBC club. If you are interested in getting one - I would first get a copy of the "Building a Small Block Chevy " by David Vizzard, and read it. Chevy made a number of compromises on the 400, and I tend to think a 383 stroker (build on a 350 block) is a better plan for High Performance street use.

Now - if you're willing to pop for the $$$ to run an aftermarket block - then forget about what I said above, and consider a 415 (3.875 stroke) - or a 427 (4.000 Stroke) with good rods, pistons and a good forged crank - but expect that an assembled short block alone to run a bit north of $5K.

 

I truly thank EVERYONE for your input. There are a LOT of opinions/information/suggestions to consider. And everyone's opinions receive equal consideration. What it all boils down to is - I am a newb on Corvettes, and am truly thankful for all of the input. My gawd - i REALLY didn't realize that my car was a "unicorn" in the automotive world, until I came here. Heck - Just my rear wheel bearing situation was a complete "Eye Opener" for me....

This forum is truly amazing, and populated by great folks. Thank You for being so informative and willing to help.

You are the best folks I've never met. :-)

Mike

 

Since my last post, I have picked up a "509 Casting #, 400 SBC (block/rotating assy/flywheel/heads/cam/lifters/rockers//oil pan) and now have it stripped down. Was still sealed up (oil was old but looked good, antifreeze also was old, but looked good. The cylinders are pristine, the pistons look sweet. Crank has no obvious signs of wear. I'm guessing this was semi-recently rebuilt, or was seriously babied. Now I just have to decide exactly what I want to do with it. :-)

 

look at the engine bearings. they will say GM 100 and a month-year date if orig. post pics of them.

 

[QUOTE=Tech141;1605834131]Howdy folks,

I know I've only been here a very short amount of time, and have stuck my nose in (maybe...) too often, but I am a curious/helpful guy by nature. As I sit here thinking about modifying my 1980 'Vette, my inner voice keeps whispering "400 SBC.....",
30 years ago I had a 1972 GMC pickup, with a 350 - at least that's what the stealership said it had when I bought it. So, the weekend came when I tore the motor down for a 100% rebuild. EVERYTHING worked/fit just fine with 350 parts, until I got to replacing the crank bearings. The ones I bought (350 SBC specs) were just a tad too small. So I took the crank down to the parts store, they measured, and we discovered I actually had a 400 SBC (this was before the internet and easy research at the tip of your fingers). So, parts were returned/exchanged for 400 specs and the rebuild went hunky dory. That motor, after the rebuild, was a BEAST.
So, to make a long story short (yeah, I know - Too Late...), has anyone put a 400 SBC in their C3?
I've been doing some looking around and see there is a plethora of used/rebuildable SBC 400 blocks/short/long assy's available for pretty darn good cheddar. AND - fitment is no problem, as except for the crank/rotating assy, 350 externals work perfectly (IIRC). I am not leery of doing the work, but is the effort worth it? Looking for input from the C3 experts that are in abundance........[/QUOTE ]
I just sold my old 406 to a buddy after running it in my 80 for fifteen years,still running strong.
You need to soul search for what you’re wanting the car to do before proceeding. Mild driver with a 400 is easy. Building a beast will cost a lot more as you blow trannies, rears, go through fuel delivery and cooling issues.

Have fun with this!

BTW My 406 was a 511 block with AFR 195 heads and a solid non roller cam. Hit 7000 with ease, blew three trannies and one rear. This from a block every one said was weak….

The only reason I went with a SHP block for my 427 was the cost of machining my 50 year old 400 was almost the same as a new Dart block.

 

I also run a 511 4 bolt block 406.......with 200 Dart Pro 1 heads, an ancient 292H Magnum cam ground on a 108 Lobe Sep, Team G and 750hp Holley......it runs an Eagle crank and rods...KB Hyper pistons.......
It makes in the upper 400's for power and torque......M20 4 speed and 3.36 rear gear......it runs HARD.....easy high 11 second car from a shelf combo, zero exotic components.

I am not an LS guy either......you open the hood of one of these and I expect to see a small or big block vintage Chevy engine......
LS swaps are much more expensive then people in magazines make them out to be.......and the $300 LS junkyard engine is total BS......they go $800-1200 for a wore out turd here and if one does end up at the pick and pull....the vultures circle over that MF'er......if you DO find a $300 LS, you will spend $2500 get it to fit and buying the other components you need.....then you have to tune it....and all this is with a stock cam which NOBODY uses, so count on a $350 cam to unlock the potential of the LS head.......
Do not get me wrong.....the lS is a bad *** piece.....but IMHO, it has no place in a vintage car......and soooooo many cars are LS swapped now that seeing one at a car show with a vintage engine in it is props to me.......AND...the vintage engine bolts right in.....no mods,oil pans or headers to purchase......

The 509 block is a good one.......look at Lars' pics and notice the studs and main cap girdles he has.....very stable setup. The nice thing about the 3.750 crank is that the rods will clear a standard base circle roller cam...3.875 stroke and above it will not.....

Reading this thread....I want to point out that the 400 and 454 flexplate/flywheel and balancer ARE NOT the same......the balancer simply will not work as the size of the snout is different......but the flexplate/flywheel will bolt up....BUT, the weight on the 454 is heavier.......I have seen this done and they shake upstairs.......
Pioneer makes a 400 flywheel.....stockish style.

Once you build a tight 406 combo....you will forget all about LS engines and 383's.....they run that good......all you need is 1.2 hp per cube to make a 480 horse combo...VERY easy to do.......bolt on shelf parts.......

Jebby

 

For those who have followed my thread on 406 ……you know that once VortecPro Mark Jones rebuilt it right…. I ended up with 559 HP and 565 pounds of torque….I would say that’s a win. Put the link to my thread below....its long, but there is some good information there on what to do, and what NOT to do on a 406 build. It also lists all the specs on my engine.

https://www.corvetteforum.com/forums...is-winter.html

 

TQ is a function of ci. So if you add 15 or 21 ci with the longer stroke times and number like 1.3 you will end up with 20 to 28 foot pounds more with everything else being the same in a 400 or 4.06 build