Hi all,

First post here, as I am new to the Corvette community! I just picked up a 1976 coupe with 23,500 original miles on the L82 4speed. It looks great as you’ll see in the pictures, and my 8 year old son and I are thrilled.

Last year we built a Factory Five Mk4 Roadster (cobra kit car) with an LS3 / TKX drivetrain. We took that heretical route because I want to be able to drive the car very often and without worry on short and long trips. And we do exactly that. I drove it drove 300 miles for my anniversary with my wife, and 600 miles for a car show with my son. There are months where we’ve put 1000 miles on the car. I even take it to get groceries and for Home Depot runs!

I want to make my C3 into a similarly dependable car, but I am also new to the car building hobby. To be honest the cobra was very simple as I ordered the kit already designed for an LS. Before that the most I had ever done was change my own oil. I’m nervous that the level of customization to put an LS into a car that wasn’t designed for it, as well as the cost, would be a barrier. For example, my gauges, headlights, and wipers won’t work on the C3. The mounts would be all wrong. Etc.

Another important piece of information is that I don’t plan to track or race the car ever. Power is not important to me, reliability is. I want to be able to take the car anywhere I want, at any ambient temperature and altitude, without worry. 350hp or 450hp makes no difference to me.

So with that being said, I’m considering two options:

1) LS3 again. I know it, it’s bulletproof, and I trust it implicitly. But it’s also very expensive and will require a lot of customization.

2) Blueprint 383 with multiport fuel injection. Pricing it all out, this would be a $10k cheaper build than the LS, and it has a 30 month 50k mile warranty. Plus it will be so simple to swap it in, as a SBC for SBC direct exchange, so I could do it with my son as a father son project and there is value in that. The issue is I don’t trust that an EFI system developed by Blueprint will be as reliable as one by GM, who spends more money on office supplies than Blueprint does on R&D. Not that I don’t want to support a small business, I just want something that is extremely reliable.

Am I wrong to not trust the Blueprint offering more? I really like the price and the warranty and want to go with them if I can be convinced. Are there other options I should consider to achieve my goal of a daily driver and road trip ready C3?

Thanks for your input!




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I should add, the L82 and 4 speed both appear to be working fine, I just don’t think trying to road trip on a 48 year old drivetrain is very smart.

There’s a slight drip of coolant coming from somewhere that I’ll find next time I have some time.

 

Why not the Blueprint engine and use a carb? It's been awhile since I have been on the Blueprint web site but I believe they offer a complete carbed engine that should be dialed in for the carbs jetting and timing wise.

 

welcome.
you will get a lot of peoples preferences.
a lot.
LS whatever is very doable and fits nicely.

junkyard motors are sold with everything.
the orig sbc blueprint eng will need vette pan, waterpump.
congrats on your membership and goals.

there are many vette quirks/designs you will need to consider.
no worries, answers are here

 

I put well over 3000k miles on a rebuilt 69 mkIV big block with tri power Holley carbs. Its not the motor, its the maintenance and the technology in it. Some will say a stock points/rotor/condenser distributor is fine if arent racing it to 7000 rpm but you have to maintain it and check it. I run a modern MSD distributor and holley electric pump. Regulate it down in they are much more reliable than off the shelf chinese replacement parts. If you can find high quality parts you can run a completely stock setup and it will be reliable. And you can run an LS with cheap chinese **** in it, never change the oil and be sitting by the road waiting for the tow truck.

The age of the car has almost nothing to do with reliability if its properly maintained. Exceptions are using a dot 4 or 5 brake fluid in original gaskets masters and calipers. The old rubber formula will swell and fail. Same with modern synthetic oil in an old fat tappet motor or muncie. The oil is too slippery it squeezes out of the lifter faces or doesnt have the right ZDDP protection and it lets the tappet/cam run metal on metal. As for the muncie the gears cant carry the oil up to yhe top of the tranny and the gears, synchros and bearings dont get proper lube. As for the rest of the motor, original seals and rubber that see the ethanol gasoline turn to mush and you end up with gooey rubber lines and leaking seals. Ive replaced all the parts in my car without doing a frame off so its all new parts....its just the quality you have to contend with

Build or buy the motor you want or can afford. Use the best bearings and seals they make. If you end up with a flat tappet motor use the oil made for it and install the newer hardened tappets and run ones with EDM oiling holes. If you can afford a roller motor buy the best lifters they mahe with bushed bearings. They will last for ever.

My recent motor failures are Carter garbage fuel pumps coming apart at the pump axle, Clevite bi metal bearings delaminating, GM branded chinese starters frying, one brand or another alternators just giving up. GM branded master cyinders and boosters just failing, probably chinese.

Buy USA parts when you can, check reviews, ask around for experiences. Some repop parts you just cant find other than at a corvette supplier, and they are chinese junk. Light switches, wioer switches, all the vacuum parts for the wiper door and the headlights...... good luck

 

What’s wrong with staying carbureted?
I trust my fully rebuilt tuned carbed 75 c3 more than I do my stock factory fuel injected 1994 c4…. I always have this fear the ECM or CCM or one of the other thousand electronic gizmos is going to bite the dust on a road trip.

I also have a carbed k5 blazer with 264k miles on it. Trust it fully too.

 

IMHO I think your totally mistaken,, For your stated use, that engine is exactly what you need. All I would change is the trans to a TKX or TKO 5spd,, and your familiar with that. Good maintenance will keep that car ready to go any day you want, and for many many years. . Were here to help ya make it happen.
Don't get me wrong, I build LS swapped cars at my work, I like 'em,, but its not what you need.

 

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my car had same mileage and i absolutely would trust it on a trip, but no way long full speed highway. You need more gears.. reliable cooling, preventable maintenance repairs, and synthetic zinc oil gives me 1979 55mph limit reliability.

 

You have a cool car collection and love that you're getting your son into the hobby with you! Both your engine choices are great and will be reliable. Is there a link on the blueprint? Is it with port injection or a Sniper TBI? I'd do Edelbrock pro flow EFI to have port injection and good tunablility on the 383.

Your L82 is likely a good engine, those SBC's are very bullet proof! I'd change all the rubber, do all the maintenance , and get it tuned up. You'd be surprised how reliable and driveable the are. The lack of OD in the transmission will annoy you more probably lol . But if you have the budget and time, do the engine and trans swap and enjoy! Post pics an document so we can enjoy the build with you. Cheers!

 

I run mine, SBC , a thousand miles at a clip many, many times. With a 4 speed turning high RPM'S At fairly high speeds. 75 -85 MPH. Basically running it all day other than fuel and lunch stops.
An I run Dot5 brake fluid. Throttle body fuel injection for the last 5 years.
I run the car hard and many long trips. Very dependable car. Yes rebuilt the engine at about 90K miles. And pretty much the rest of the car recently.
Don't over think it!


On my way back from Cairns, Queensland Australia. About a 1,000 mile drive.

 

Thank you all so much for the responses. To respond to a few questions and points:

I think staying carbureted probably makes the most sense for people who understand how to work on them, purely for simplicity reasons. But for me, unable to do that, I would prefer the better fuel economy, cold start ability, and freedom to run at any altitude that comes with EFI. So I’m currently not considering any carbureted options except what is currently in the car until I’m ready to swap.

Here is the Blueprint I’m interested in: https://www.jegs.com/i/Blueprint-Eng...BoC1mIQAvD_BwE

The EFI system on that engine is home grown, it’s not Holley or Edelbrock. It’s Blueprint.

I’m wondering whether or not they would be able to make 4 modifications :

1. Lower the compression ratio to 9.2 or 9.0. I don’t want the extra power, and I do want less stress on the motor.
2. change to a low profile air cleaner for hood clearance
3. Change to whatever oil pan I would need for fitment
4. change to a water pump that doesn’t have a fan mount, because I’d like to switch to a Dewitts radiator with electric fans

If they can make those changes, I think this would be a much easier swap to perform than an LS3, but I still worry about the long-term reliability of this over a GM crate LS3…

Regarding the use of my current motor. I’m willing to give that a shot for a bit to see how it goes. What is worth replacing immediately for peace of mind? I’m assuming my coolant leak will be coming from a worn radiator hose, so maybe both of those along with a coolant flush? (I’m out of town so I haven’t been able to look yet) And an oil change. Not sure what else is worth immediately doing for preventative maintenance?

Lastly, there was a comment about stock motor with throttle body fuel injection. It seems that I see mainly horror stories about the Holley sniper, which is why I was really only considering something with multi port fuel injection. Have people had good success with the sniper on the L 82 engine?

thanks!

 

ABSOLUTELY,,, but nothing is flawless. I personally would not use Holley, because of experiences, ,On my '75 I have FiTech, and Aces is comeing on strong lately. Find someone near to you with what you think you want and have them tell their stories about it....

 

If power is not important to you.... why not tune up the L82? It will be just as reliable as anything you replace it with and you will save a lot of money for other things

 

if a bone stock Chevy sb cant do want you want then its wore out, and out of tune, and needs help.

 

Two reasons why I thought this, but I’m open to being educated if I’m not correct!

First, I assume that a brand new engine with a warranty would be more reliable than a rebuilt 48-year-old engine. All of the parts being brand new just seems like a better set up. My main goal with the build is this: be able to drive far away, and not get stranded. That’s it.

Second, is it really that much cheaper and easier to pull the old engine and have it rebuilt with EFI? I assume that by the time I get done with that process it would have been comparable to buying a turnkey crate engine. I’m not interested in keeping it carbureted, so the EFI is happening either way.

 

then that machine shop and builder has no clue what they are doing

 

I have a BluePrint 383 carbed engine in my 76. Plug and play only WP needs changed to Corvette specific one.No issues 7 yrs 15k+ mi.Tons of power.

 

Maybe Im vain but I trust my own work more than a stranger.
plus its wayyyyyy more fun to do it yourself

but if your dead set on those two, I’d go with the BP 383 over the LS3

 

A '76 L82 with only 23k? You currently own a very reliable motor...
My old L48 with 78k on the clock hasn't been touched & I'd trust it to go anywhere.

Just remember. A 48 year old car has a lot of other things that can break too, and they will..

 

SHORT REPLY:
Drive the car, learn it's weaknesses, address those, and enjoy. Don't throw time and money at ghosts.

LONG REPLY FULL OF FOOD FOR THOUGHT:
This is the typical logic of the inexperienced and new to old cars curious people. A new rengine will be the same experience as their modern Toyota, Chevy, or whatever. Turn the key and go and never worry about break downs. Go over to the C8 forum section here and read all about brand new C8s breaking down. Also, many of the aftermarket parts used to build a "new" replacement engine are of old design and still prone to the same failures. They are also unproven unlike your 26K mile L82 engine which I assume will turn key start and drive around. People tend to see a problem like a coolant leak and assume this is the first of many repairs so rip it all out and start over. Why not drive the car as you intend and learn the car and how it runs? It looks beautiful on the outside, low miles, and cared for. A very important thing to do with any vehicle, be it a 3 year old used car new to you or a 50 year old car bought for fun, is to go over every system in the car looking at everything to learn what might be a problem now or in the near future.

Here's another viewpoint. I have a 46 year old Corvette. It is fairly original with common service parts having been replaced over the years. A stock 350 engine with 4 speed manual transmission and 3.36:1 rear end ratio. The carburetor is the original to the car and hasn't been apart. I have 40 years active experience working on machines. I like to use these machines. When I got this Corvette I went through the systems inspecting them and figuring out their health. For the most part it just needed basic things I did while using the car. My wife and I use the car for scenic day trips which are on average 150-250 miles. We've also driven it to Corvettes at Carlisle a couple of times which is about 1,000 miles round trip (~450 each way). Those trips are a full day on the highway, car is very comfortable, its quiet inside and we talk at normal quiet levels, and at the end of the day we are no more fatigued than we would be if we had taken our modern daily driver luxury car. After 4 years owning this Corvette and 11,000 miles the car has never broken down and I have never touched the carburetor. This isn't my first carbureted vehicle and most I've had were daily drivers year round rain, snow, or shine. There isn't anything bad about a carburetor but they couldn't be as efficient as fuel injection is and that's the main reason they aren't on cars anymore. Do you have a gas lawn mower? A home standby generator? They most likely still have carburetors. Do they randomly not work?

Speaking of snow, the old saying that if you buy a new snow blower or snowmobile is then there won't be any snow that winter.If you buy a new engine because the original engine is old what is the next weak link? . If you replace the engine will the rear differential fail and strand you instead? Its that slippery slope kind of logic. I don't know something so instead of learning and experiencing I will get a "new" something and no longer worry. False logic. It gets extreme in the car hobby now because of the "old" concept. People take just the skin of an old car and hang it over a modern car. It will look old but be new. And 99% of those conversion don't get driven when done.

A new engine with a warranty does no good when it fails while on one of your trips. You are stranded. A low mileage original engine that is checked out and healthy is a proven non-Lemon. Again, go read the C8 forum threads about brand new Corvettes breaking down. New things are often Lemons and it has gotten so much more common in the past few years. Lots of inferior products, sub assemblies, bearings, seals, and software/firmware. Computer glitches are more common now too. A 1976 Corvette has ZERO computers. Fix a couple engine problems as you learn the car OR replace the engine which is 1,000 parts or some pretty large number of parts = ??? problems.