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........

 

I had a 406 built, mostly aftermarket parts, starting with a Dart SHP block....and it was quite a performer....but expensive. The builder made massive mistakes, and the engine is now at VortecPro getting fixed. When I decided to go with this engine, I researched using a factory block.....but seemed to me they had some weaknesses, and were not as common to find as I had hoped. Many have been built and abused....the block really needs to be checked before building. The Dart SHP block is more expensive,....but has lots of improved features.

 

the 400 itself was built as a low perf truck and station wagon motor. it didn't get used that way long. you hear about 406, 427, 434 and larger small blocks. they are all based on the 400, not the 350 design. if you can find a real 400, go for it. i put one in my sea ray. snapped the driveshaft in my outdrive...

 

ive been on the lookout for a cheap one to rebuild locally for a while to do just this... theres lots of c3s running around with 406's and the like.

 

I've got one in my C3 and love it....I built the engine as a sporty street performer and it does this really well, but it's all over at 6000 RPM which is exactly what I wanted....(lots of torque down low.) This combined with a 5 speed tranny is a really fun street ride.
If you stick with GM blocks and get some longer rods (mine has 5.7" rods) and go with a small base circle cam it's very easy to do.

My .02

 

I'm running a 407 (400 SBC +.030 = 406.8) in my C2. Easy 500hp with 500 ft/lbs torque, so it's brutal on the street with the 3.73:1 rear and 4-speed. Solid roller with some nice forged pistons & rods (6-inch). I fabricated and installed main cap retaining bars and used studs on the bottom end of the 2-bolt block. RHS heads. I run 6,500 rpm shift points, but it has no problem with 7,000 rpm (although it's on the back-side of the power curve after 6500). I got the block and crank for free, because nobody wants a "stupid 400 truck engine." The 400 is a sweet, torquey setup that will rev with anything else. Do it!


















On the dyno - it's an honest 500/500 motor:


All dropped in a nice all-stock car... nothing to see here:


Lars

 

or a hybrid , Dart large bore block with 350 mains , 400 bore and 350 mains , we have one going on the dyno next week 427 SBC with hydraulic roller custom grind and Brodix 18X cylinder heads

 

don't go looking for a 4 bolt. the 2 bolt is stronger. if you find a 4 bolt, take it. but it is not an upgrade. they drilled into the 2 bolt webs for the extra main bolts. and weakened the webs in the process. not much, but measurable. you want real power, get a new aftermarket block. they improved on all of chebbys good ideas and cleaned up the bad ones...

 

There is a complete (minus starter...) 1971 400 SBC not very far from me for $600........ #1511 block...... But what will I need to do to get it to work in my 1980?......... Decisions, decisions, decisions........

 

you will need the 400 flywheel and balancer. the rest will bolt right on. hell the wrong flywheel and balancer will bolt on, but don't. a guy sold me a 454 flywheel for my 406 in my boat. same casting number but balanced different. the bow rails shook like the front forks on a 650 triumph at idle. it is a chebby small block. it will bolt to the mounts, brackets, bell housing, intake, valve covers, oil pan, everything. just external balance so it needs different balancer and flywheel.

 

LS swap...

 

this^ if you are able to do the swap, it will bring modern reliability, economy, efficiency to your vehicles for low cost.
ex.
A $300 5.3L 'LM7' From 2002 Tahoe, Escalade, Silverado, etc...
All factory engine, with 150k to 250k miles,
will support around 650rwhp (800bhp) for 100k more miles, if properly cared for.

No need to spend all that $$ on the engine anymore. LS block is far superior to all Chevrolet before 2002.
In 2005 they make a 5.3L L33 variant, all aluminum engine, capable of 1000rwhp (1250bhp) all stock bottom end.
It also weighs less than the iron 4-cylinder from many modern vehicles such as Nissan and Toyota.

My 5.3L LM7 installed in 2017 I put 50,000 miles on it in 5 years, 500-600rwhp turbocharged, 93 octane gasoline only.
Have not done anything to it at all, ran out of things to do. Drive every day.
Caveat... you must be an amazing tuner capable of wiring, fabricating, setting up everything perfectly yourself.
I Detail how everything needs to be done. Must be turbo. Must use proper air filtering. Must measure crankcase pressure. And so forth.

 

I would vote yes on the 400. Likely be the only guy in your county that has one. They could make a 4500 pound Impala move right down the road. In the early 80's put one with a 400 turbo behind it in a 67 Landcruiser. Stab the gas pedal taking off from a stoplight and it would really pin you back in the seat.

 

yes the LS is superior in every way but one. the ability to attach to the wiring, fuel system and everything else that came under the hoods of these cars in the 60's and 70's. and few of us are capable of rewiring, etc every system in the car to turn it into an 03 silverado with a C3 body. in this case, the OP didn't know what is needed to install the 400 small block. he for sure is not far enough along to do an LS swap. and i am not trying to insult Tech141 . nobody knows stuff they do not know. doesn't make them stupid. in fact, those of us that know our way around all the systems of a 50 year old vehicle could be considered the stupid ones for spending too much time and money on too many old cars...

 

Modernizing the C3 is just not in keeping with the spirit of a classic car to me.
Sure an LS would be a big upgrade and leap in technology. But why stop there if being more modern and “technologically better” is your goal.
Make it electric and make it AWD now you can go from 0 to 60 in 3 seconds.
electric car enthusiasts would say it would be a waste of effort to bother with an LS engine or any ICE for that matter. Turbo chargers, fuel injection, intakes and exhaust, all could be eliminated. No oil changes or plug changes, tuning, air filter replacement. All the things that would be eliminated by just going electric.

Personal preference comes into play. I prefer to stay with the tech if the era, or at least close to it and preserve the nostalgia of the car. Modernizing it, changes it In a way I find undesirable. Even as simple as an X pipe would make exhaust better. At the cost of the sound. That sound goes with the era of the car and I want to retain it.

To each his own I guess. I think a 400 SBC is an excellent choice of an engine. SB size and weight with BB like performance.

 

If I had a 400 from an automatic what flywheel would I need to install it into a stick shift car and does the balancer need to be changed also?

 

300.00 dollar LS's are falling out of trees everywhere but here. Grab while you can . Now if you get a Scat stroker kit for the 400 to build a 427(.030 over ..or.. 434 is .060 over stock) it will be internally balanced and no need for fly wheel or harmonic balancer change , if you keep it 400 inches you will need fly wheel and balancer

 

you would need a 454 flywheel for the 400 to keep the balance .. 400 sbc and 454bbc share the same harmonic balancer and flywheels

 

I see 400 sbc's come across Facebook Marketplace every few months (upper midwest area). I'll keep an eye out and shoot it your way, OP, if I see one.

 

Here ya go: http://www.facebook.com/marketplace/...86560238092138
2-bolt 509 casting block for $400.
Also saw 3 or 4 others in various states of build, but I figured you'd be more in the market for a block?