Good Afternoon everyone-

merry Christmas. I just picked up a 76 C3 after looking for one for about a year and a half now. Car is beautiful and in really great shape. As we all know under powered. I went this route vs th chrome bumpers really to off set the feeling bad affect of changing anything around on the car. I’d value some feedback from you all about dropping a crate motor in vs doing a top end rebuild. I’m not trying to set records. My game plan was either putting in the blueprint 350 (390 hp) or doing the whole top end and keeping the block…regardless will also be upgrading headers and braking system. Not trying to create so much power that I need to start messing around with the rear and suspension. Just a touch more go. Anyone who has done a build of similar would you share parts list? There’s an overwhelming amount of info and trying to narrow down off of real time feedback and proven success!

thanks all

 

While I have no input of value as to your questions/goals, I do want to congratulate you on your new and very pretty ride. I’ve always loved silver with a red interior!

 

I would go with the crate motor. The existing block has low compression pistons, and may be just worn out due to miles (which you didn't say how many). For a proper rebuild you should pull the motor anyway, so why not go with a swap?

 

Congratulations on your new to you toy. Looks great!
As per your performance needs. A lot of that depends on how much you can do yourself, The condition of the engine now and of course your power requirements.
And of course what's behind the engine.

 

To already have a clutch pedal! If you do the math, and do the work yourself, you will not be able to beat a junkyard LS swap for a cost effective solution. Otherwise, a crate engine is your next best option.

Good luck. A C3 and a C5 is the best pair of Corvettes!!

 

Welcome to the forum! Beautiful color combination!

Here is my build thread about putting more power in my ‘76. It’s definitely enough to warrant looking at everything in the entire drivetrain though.

Before making any changes to the engine itself I would look into a true dual exhaust system and optimizing your ignition curve. Headers like you mentioned are good too. Those two combined some of the easiest/cheapest modifications to do and the exhaust will need to be done regardless if you plan on changing engines.

 

Keep it as close to original and it will always be worth more money in the end. I would choose to rebuild your existing small block and keep it as original looking on the "outside", but beef that small block up and make some serious power with it while looking stock...

The factory engine is lame with low compression and lame cylinder heads. Put some compression into that engine and some heads that breath and the beast will appear out of the smoke! Easy fixes for a D.I.Y. mechanic with some tools.

I considered the LS swap a while back but decided the BB power was sufficient for me and it was the right engine for my C3. Your engine would be able to support sufficient power to make you happy with a bit of work.

Get out and enjoy the Corvette for a few months while making a list of items for the punch list. Then you will have a list of things to start fixing her up the way you want the car.

Best regards,
Chris

 

Nice looking '76; 4-speed and those gorgeous OE-type sidepipes to boot !

First, please tell us reliable mileage on current motor ?
There're all sorts of opinions; I for one also like the course of a rebuild-upgrade of OE motor by a nearby shop.
And, in this matter, many of the best shops and builders in the nation are within an hour's drive of Lake Wylie SC.

Next, do You & Yours have a suitable, long-term place to store a five hundred pound OE motor ? And, Is everyone on board with you storing its OE engine ?

FYI. Most crate motors (including the one you're favoring) have warranty that Requires any legal claims arising from motor, to be Filed and Adjudicated FAR Away from Lake Wylie; you can read those terms in sellers warranty (published on-line) And Your attorney can confirm same. It's likely same attorney would also suggest cost of pursuing an interstate claim of $5K - $10K is prohibitive, if not impractical. Those interstate sellers KNOW this as well. Promises are one thing, But our Courts exist for when promises aren't kept or whenever reasonable expectations aren't met. Suggest both read and understand Any sellers' warranties.

OTOH, General Motors' crate motors have the best warranty in the business AND THEIR warranties are entirely enforceable in any jurisdiction within the USA.

Suggest Either have your OE engine professionally built around Charlotte Metro area, OR buy a brand new crate engine marketed by either Chevrolet Performance or GM Powertrain.

Merry Christmas

 

Blueprint crate engine all the way!

 

Crate 383 and an overdrive manual transmission. Probably need to know what your budget is.

Leave the rear end alone and just make sure the brakes are working properly. No need for "upgrades" there. JMO.

 

Nice car keep it stock . Compare crate with local rebuilder if you can find one with a good reputation from a Local independent corvette shop .

 

Does it have base engine or L82? I agree with what others have mentioned, good to keep the original engine in it. Plenty of ways to get very good horsepower out of the stock 350. Even if it costs a little more to build it up than to just get a crate motor, I think it's worth it.

I recently got a '73 with the stock L82 built up into a 383 stroker. I feel much better having the original motor in it than if it were a crate motor of similar specs.

 

Suggest do Not limit, or even focus, an Engine build shop choice to 'Corvette' shops.
Here, In OP's range (Charlotte NC's Queen City Metro area), there are a unique abundance of pro builders; and Most thereabouts certainly ain't at a vette store/shop.

That area once did include "DUB" who was an overall great vette pro to include motor work. Sadly, Albert “Dub” Dubnicka passed away in August 2022. He owned and operated Corvettes Etc at Charlotte
May our Lord and Saviour Always Bless and Keep Albert +

 

I would go LS and whatever tranny trips your trigger.... but I really like having overdrive.

 

Personal opinion only!

Our cars are getting really old now, even the less desirable mid to early 80's C3. Keeping OEM components original ,as much as possible, will always be more interesting to most car enthusiasts, down the line, even when we are long gone.

To me, putting an LS motor in a C3 makes the car not a C3 true to the GM intent, good or bad.

Same for a crate motor, blueprint or not, X2 for a 383, a motor that never came in a C3 (yes I know, no one will know it is a 383, unless you tell them). I see the LS or crate engine more appropriate for more run of the mill older cars..again my opinion only.

With all my opinions shared, I chose the following after my consultations with this forum, what I learned over 40 years working mostly on Chevy's as a hobby, and a local expert builder in my area. If your base is an L-82, I would no question try to preserve the block and use the L-82 components. When I rebuilt/upgraded my OEM L-82 4 speed with 66,000 miles on it in 2014, I had the block bored .030, did NOT deck the block since it was straight, reconditioned the L-82 OEM rods, Reconditioned the L-82 OEM forged crank, Mildly ported the Aluminum L-82 intake, reused the HEI distributor, reused the most of the external components including the stewart Stage 2 aluminum water pump, Holley carb, Comp Cams 1.5 roller tipped rockers, etc.

I purchased new JE Forged racing pistons, AFR 180 CC 64 CC aluminum heads, howards roller cam .525 lift/219/225 duration, LSA 110 (Operating range 1,500-5,600 RPM), new motor mounts, new fuel pump, etc. The total cost for the short block machine work, short block assembly, everything else by me in my garage was total cost of $5,500 which was actually slight less than the Blueprint 383 back in 2014, making probably more power with better quality components. My 355 L-82 pulls strongly off idle, has BIG mid Range torque (2,500-4,500 RPM) and will scream to 6,000 RPM with the 4 speed and 3.70 gears. Not sure you could build the same today for similar dollars to a crate 383. I have never had any second thoughts on building the L-82 back to and exceeding the potential of any factory stock C3 350 that came from GM originally......

With the money saved, go for an overdrive tranny.....

 

My two cents-assuming your original engine is sound (good oil pressure and compression) go for the top end kit, Edelbrock, Summit, Jeg's, etc. 64cc heads will bump the compression to somewhere in the neighborhood of 10:1. the components will be matched from the manufacturer so you know they'll work together. you'll end up with probably more than twice the original HP and that will give you some thrills when you hit the skinny pedal.

 

OP has not shared much info about his OE '76 C3 motor; dunno if ZQ3 aka L48, or L82 ?
If it's an OE '71-Up BASE C3 motor, it will have OE 4VR dished aka sumphead pistons. While L82 have flattops with a single groove 'trough' valve relief.
FWIW, a 64cc chamber atop an OE dish piston 350ci cannot come close to 10:1 SCR; no matter gasket thickness. OE Flattop will make about 10:1.
In my neck of the woods, 'top end' includes pistons-rings too; while 'bottom end' includes crank & rods. YMMV

 

Lack of a hood badge makes me think L48. That’s not to say it hasn’t been changed to anything better or worse from what came in it from the factory.

Here is a good thread about getting more power out of an L48.