Dorian’s Big Block C3 build


solid fixture here in the forum
Staff member
Hi All…

I am carefully lining up all my ducks here. As some of you may know, this Saturday I finally sold the TT. It sold reasonably well. This has freed up the resources I need to purchase my next project car: a C3 corvette.

What some of you probably have been suspecting for a while is that I already have a nice, unmolested, Corvette in mind: Richard’s (aka Chromebumpers) 1971 T-top.

The TT was incremental in build and it was a great learning experience taking me 15 years to get there… and probably more $$$ than it could have if I knew where I wanted to go from the start. So we are going to do this build "Grumpy-style": establish a goal first and build toward it.

After reading through the other threads, and particularly looking at Indy’s awesome build and the responses to “another 383 build” thread… I have come to the conclusion that this time I want to build my own Big Block. They are very uncommon here and I have always wanted to do one of these.

I have a mild concern about the way the C3’s handling will be impacted with such a heavy engine… Suspension will need to be beefed up, no doubt.

The parameters are:

- I build the engine (fun!)
- Excellent idle
- Excellent street manners (not to come across as sexist but a lady should be able to drive it)
- Durability and reliability
- Reasonable 1/4 mile times

So at this point other than reassuring me that a BBC will not turn the C3 in to a laundry iron when it comes to handling

Let’s put a parts list together so I can start plotting over the long term and gather the components as I go.

Additional questions that need answering: the C3 is a stick shift and will remain that way. It is for street use and will see VERY little if any strip. I don’t care about the CID. Pump gas. Reasonably priced parts – not super exotic titanium retainers and aluminum block. If a 454-short block works… why not? 572 is not too crazy… sure!

I can’t think of anything else that needs answerin’

Oh, I expect it to take me 2.5 years to afford, collect and build.


The Grumpy Grease Monkey mechanical engineer.
Staff member
you can forget about any significant handling issues, lets look at a few facts
(1) a big block with aluminum cylinder heads, intake manifold and water pump weights LESS than 100 lbs more than an iron small block,
ditch the cast iron exhaust manifolds and its closer to a 40lb-to- 70lb difference.
if you use aluminum heads, intake and water pump the weight difference is far less than youll see just filling your gas tank
sbc engines weight about 100 lb less than a BBC with an iron water pump, heads and intake,.
swapping those components on a big block too aluminum gets the weight very close to the factory sbc,
I don,t know a single c3 big block owner that has a properly built BBC engine and a manual transmission that feels his car lacks power or handling compared to a similar corvette with a factory sbc engine, and Id point out that theres a ton of aftermarket components that allow further weight reduction and much improved handling over the stock suspension
I would think you would have decided to go with a big block, simply because theres a huge potential difference/increase in torque and if the correct parts are used only about an 80 lb difference the weight, that difference in power far offsets the minimal weight difference, which is far lower than simply having the wife or girl friend in the pass seat

(2) your average early c3 corvette weight, was close to 3200 lbs with a SBC and about 3350 lbs with an iron head big block
(Ive weighted DOZENS)
the most famous big block performance engine was arguably the 427 L88 that produced about 530 factory horse power
if you build a 496 bbc (what ID advise you can easily exceed that power without the radical cam and high octane dependent high compression engine specs.
stock SBC corvette lets say you have 350 hp and 400 ft lbs and weight 3200 lbs,
9.1 lbs per hp
same corvette with aluminum component bbc engine
lets say 500 hp and 600 ft lbs at 3350 lbs
, 6.7 lbs per hp
a boost of 50% in torque and roughly 30% in horse power is very noticeable
and thats very easily increased

which one do you think is more fun to drive and much faster







I came too the conclusion decades ago that if you want something, that look ,sounds, and performs impressively your rarely disappointed with a correctly built big block chevy.
I build more BBC engine that almost all the rest combined and most are not all that radical, just street/strip muscle car engines, Id be happy to give you some insight and parts suggestions , I know you can build something that will provide the car with impressive performance yet still maintain a good deal of daily driver comfort, the extra displacement, better heads, bigger valves etc. do have marked advantages.
guys have been racing big block, and especially L88 C3 corvettes and running at impressive speeds and maintaining good handling since the 1968 c3 vette was introduced,mods to the brakes and suspension better tires and adding some arodynamics will of course allow much higher speeds with a c3 corvette.
bargain big block chevy heads, and some related info
When your planing to build a performance car, I've found it helps,
you see progress being made and prevents you from getting discouraged as easily,
if you work on accumulating components for each of the 8 basic sub assemblies,
and checking off your list those components and grouping those on a separate shelf,
as doing so tends to allow you to see more consistent progress,
being made, and you get a feeling your getting someplace.

(1) BLOCK (bearings, freeze plugs main caps and machine work)

(2) ROTATING ASSEMBLY (crank, rods pistons, rings, flywheel,damper etc.)

(3) CYLINDER HEADS and VALVE TRAIN ( valves, valve springs, cam, timing gears, rockers, valve guides, push-rods lifters . etc.)

(4)INDUCTION(manifold, throttle body, sensors, carbs, supercharger, injection , fuel pump, fuel pressure regulator injectors etc.)

(5) DRIVE TRAIN ASSEMBLY COMPONENTS(clutch, stall converter, transmission ETC.)

(6) ignition system (distributor,coils, ignition wires, magneto etc.)

(7) LUBE SYSTEM (oil pan, oil pump, windage tray,oil cooler, ETC.)
these threads and links and sub-links might help

(8) EXHAUST (headers and exhaust system, mufflers ETC.)


A fairly mild hydraulic roller cam like this
a decent set of heads, intake , road race oil pan, about 9.5:1-10:1 compression, and 600 ft lbs and 500 hp is easy

what your basically looking for can be easily provided with a set of decent quality oval port heads, a dual plane intake intake matched to a 454-496-540 big block (the larger the displacement the smoother the engine will run and the more massive the torque curve will tend to be, a 496 versions an excellent compromise) with a fairly mild hydraulic cam, and a 750cfm-850 cfm carb, and low restriction headers and exhaust, you'll be rather amazed at both the off idle torque yet docile ease of drive-ability and potential power available without needing the radical idle or need to build rpms before the car will pull briskly in traffic
800 rpm idle, brisk acceleration, in traffic when you want it, you still have power brakes and
a low rumble to the idle but no bad drive-ability issues,
and you'll never need to break 5500 rpm,
and rarely have any need to push past 3500 rpm in a daily comute










ID suggest you select from heads from these sources
Jegs; 800/345-4545;

Summit Racing; 800/230-3030;

Scoggin-Dickey Parts Center; 800/456-0211;

TRICKFLOW ... 4294867081
1-330-630-1555 • 1-888-841-6556


Dart Machinery; 248/362-1188;

toll free: 877-892-8844
tel: 661-257-8124

Patriot Performance
Patriot Performance; 888/462-8276;

Toll Free: 877-776-4323
Local: 901-259-1134

EDELBROCK ... main.shtml
Edelbrock; 310/781-2222;

BMP (world products)
Tel: 631-737-0372
Fax: 631-737-0467







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solid fixture here in the forum
Staff member
Btw, with a quarter tank of gas and nobody inside this Corvette weighs in at 3137 on the shipping scales at Fed Ex scales , Philadelphia Airport and my hydraulic pressure scale on my Mohawk lift it was 3192 with a half tank.


solid fixture here in the forum
Staff member
And with a full tank of gas and half a pack of cigarettes???? :cool::cool::cool::cool::D


solid fixture here in the forum
Staff member
Thanks Grumpy and Gents... a lot to read through there.



solid fixture here in the forum
Staff member
Wow! Those factory low and wide valve covers, perfectly painted red on Big Blocks are so sexy! LOL! Even in chrome BBC are unmistakable! I want to adopt one! I might just trade my GTO for a 1st gen Camaro with a BBC! Hehehe!


The Grumpy Grease Monkey mechanical engineer.
Staff member
yes the suspension on the car in question was obviously not set up optimally, the sway bar selected on both front and rear, the shocks and suspension spring rates and obviously the tires in use were way off of the correct selection.
tire tech alone has advanced immeasurably in the last 30 years.
when I was younger I was into building engines for the local road race and circle track racers far more frequently than I do now, but I remember helping to install a few of those engines in cars that raced road racing tracks and I can assure you the successful cars were not running pure show room stock suspension components, or brakes or tires, or cooling systems.
even with the 100 lbs difference in weight up front,between the big block vs small block engines the difference in handling is minimal in a correctly set up C3 corvette, if you ever watch the videos of the L88 C3 cars running at sebring Florida you'll see they have little issue with handling and impressive power, and keep in mind those cars 427 L88 engines were by today's standard not nearly as powerful, as what you can build now and were far less street-able than what can be assembled with a larger displacement lower compression combo that weights less now.
in a properly set up c3 corvette, I doubt youll see any significant difference in the cars handling from the additional 60-100 lbs of weight of the larger engine, all that weights behind and not above the front axle , and with proper tires, shocks and bushings etc the difference in available power helps off-set the minimal weight once the driver learns the cars characteristics the cars I see race at SEBRING were mostly big block c3 cars

heres a direct quote from a c3 big block corvette road race car owner

Assuming the OP (or subsequent viewers) might have been looking for advice on how to go about the actual sorting process...

First rule of chassis setup/tuning: Only make one change at a time. Otherwise you won't know what changes actually improve things and you can easily get lost.

Second rule: Only make changes based on diagnosis drawn from testing.Bypassing this step and simply throwing a catalog at your chassis WILL leave a good percentage of untapped potential on the table, however glowing may be the reviews of any particular set of kit. So, bear in mind that what works for someone else (myself included) isn't necessarily going to best suit your individual circumstances (car/purpose/rules/skill...). And, guessing without having a decent grasp of what you're doing can turn into a recipe for ending up in the Armco. I would urge anyone truly serious about actually sorting their chassis for tracking to study up on the basic fundamentals, to develop a sensitive backside, and learn how to evaluate tire temps with a tire pyrometer (an IR type will do in a pinch).

Third rule: Don't confuse how a car seems to handle at less than 10/10ths of its limits with what its actual handling and drivability characteristics will be on the edge. A car with final oversteer will often feel like it is on rails right up until it bites you.

My basic setup philosophy, vastly oversimplified:
Work from the tires up.
Stiffen the frame and reduce suspension compliance.
Reduce weight without compromising safety, and work to improve weight distribution and lower the CG.
Get the suspension geometry right, not only including static alignment and ride heights, but to also minimize bumpsteer, rear toe-steer, scrub, and to optimize roll centers and camber gain.
Use as much spring rate as practical/tolerable to balance the car and control roll (notice I didn't say "eliminate roll"), as well as dive and squat, while being careful not to install more rear spring than absolutely necessary, and only relying on bars (think of them as crutches) as secondary or fine tuning tools. You do NOT necessarily need a rear bar, despite what people try to sell you.
Shocks aren't just for controlling unsprung weight, but also for tuning how a car transitions into and out of corners by regulating the speed at which weight transfers.

There is much more, of course, but the above will hopefully give you a basis from which to work. My $.02, no charge.



I wouldn't over-estimate the impact of the BBC's additional weight on handling. A BBC with alum heads (money well spent), intake and water pump is less than 100# heavier than an L82 SBC, and that weight is behind rather than above the front axle. IMOE this can be fairly readily compensated for with some BBC-appropriate chassis tuning and a little weight savings elsewhere. And, if you'll strive to control rear roll with the spring rate you can avoid the traction penalty on corner exit acceleration had by running a rear bar, which means you can pick up the throttle earlier. I'd also suggest that you wait and see just how much you actually need to reduce rear camber gain before spending money on drag strip oriented kit (per the "2nd rule" in my earlier post).








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solid fixture here in the forum
Staff member
Well, you got me convinced both ways… that a C3 corvette can be made to handle reasonably well and nimble… certainly much better than my old Chevelle, yes? Certainly the weight with select aluminum parts is not so off.

Also a stout 496 seems the way to go. I am looking at short blocks… Summits has two. Essentially with flat top or domed pistons. Any recommendations there? For a daily driver, flat top should be fine, no?

Do we have any links on C3 corvette suspension mods? I have seen some kits that modify with coil over shocks in the rear… different upper arms… anti-sway bars… and of course tires. I am wary of these companies that throw out all OEM. Surely OEM was reasonable as well. Lower profile tires seem requires as well for good handling.

PS Am I seeing wrote or does this guy have a tube blowing cool air on his calipers?


The Grumpy Grease Monkey mechanical engineer.
Staff member
its standard procedure to have air ducts directing cool air at the brake rotors on road race cars.

theres two links at the bottom of the post above, for suspension parts suppliers.

and don,t forget your selection of shocks, poly suspension and frame bushings help a good deal, front and rear springs, front and rear sway bars, tires, rim diam. and width, and the factors like your cars toe in/out , settings and tire air pressure and rubber compound do matter to performance.
but Id also point out that driving skills and experience mater a good deal and while the corvette will vastly out handle the old TT, it will also require the driver to learn new skills and gain experience, you'll be able to do things the old TT could never attempt to do, but that also means you could screw up, if you push things , in the car with its much improved handling ability, too far with the much better handling and braking you'll very quickly come to like and depend on (provided of course that you set up the car correctly)
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The Grumpy Grease Monkey mechanical engineer.
Staff member
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The Grumpy Grease Monkey mechanical engineer.
Staff member

yes your correct you can,t change physical laws, the sbc can be built with aluminum components and built lighter and have a slight handling advantage, but if your running laps at a track like lemans or sebring the far greater acceleration and top speed of the big block wwith its extra torque and peak power far off sets the dis-advantage in handling that the minimal extra weight penalty imposses .
thats why the guys racing the L88 corvettes were generally using that engine vs a 302 sbc like the trans-am cars used
L88 corvette race a different class than z28 corvettes because they are not similar handling and certainly not competively powered cars the corvettes have an advantage in both handling and power.
Id also point out that building a 540-572 BBC today . with the much stronger aftermarket engine blocks and much superior cylinder heads and solid or hydraulic roller cams available now, makes the car potentially no heavier but adds a great deal more torque and peak power potential at lower rpms than the 427 L88 of 30 plus years ago, and almost all the things that made the 427 L88 engine fast in a corvette, can be done much better with todays parts and tecnology and a larger displacement BBC engine
the answer too what cooling system is most likely to both cool the car/truck efficiently and fit your budget,would mostly depend on your budget limitations,
but a large 3-4 tube aluminum radiator with a a 140-to-200 amp alternator
taking advantage of all your options is a smart way to reproach the issue of correctly controlling, and maintaining a stable and predictable engine heat level, thus installing a larger capacity racing style oil pan and an auxiliary oil cooler with an electrical fan, will significantly increase the engines ability to rapidly dissipate heat even before that engine heat is absorbed by the engines cooling systems coolant. oil flow over a few of the hottest components like valve springs, bearing surfaces,and rocker arms absorb and transfer heat to the block, and oil pan as it flows, thus a larger oil capacity and a baffled oil pan with an extended sump is a good idea as the increased oil capacity and larger surface area of an enlarged sump area exposed too outside air flow can stabilize and allow a good deal of heat to dissipate to that outside air flow, as the air which can be well over 130F-170 plus F cooler that the engine oil that can be up to 250F plus in a racing engine






I'd point out that a 7-8 quart baffled oil pan helps cool an engine.
and dual or a large single electric fan with a matched ducted shroud and the ability to move,
2500 fcm-3000 cfm of air should provide adequate cooling for most engines.
adding an auxiliary oil cooler certainly helps

Keep in mind a well designed 7-8 quart baffled oil pan adds both durability and helps reduce cooling issues

and if you have an automatic transmission Id add a electrical fan cooled trans fluid cooler



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The Grumpy Grease Monkey mechanical engineer.
Staff member
IF you want mega horse power (obviously not the intended route here, )obviously you have options and you could easily install a performance LS series , performance engine,
your hardly the first one to suggest that LSX option, but Ill point out a couple potential minor flaws in going that route.
first the $24K price tag for 770 hp,
Part Number:

Engine Type:
LS-Series Small-Block V-8
Displacement (cu. in.):
454 (7.4L)
Bore x Stroke (in.):
4.185 x 4.125 (106.3 x 104.8 mm)
Block (P/N 19244057):
LSX cast iron with six-bolt cylinder head attachment
Crankshaft (P/N 19244018):
4340 forged steel
Connecting Rods (P/N 19166964):
4340 forged steel
Pistons (P/N 19166958):
4032 forged aluminum
Camshaft Type (P/N 19166975):
Mechanical roller
Camshaft Lift (in.):
.738 intake / .738 exhaust
Camshaft Duration (@.050 in.):
250° intake / 270° exhaust

Cylinder Heads (P/N 19166979)
Drag race cylinder heads six-bolt LSX aluminum

Valve size (in.)
2.250 x 6.370 intake / 1.625 x 6.400 exhaust
Compression Ratio
Rocker Arms (P/N 19201808)
Shaft mounted with needle bearing fulcrum and tip
Rocker Arm Ratio
Recommended Fuel
Race fuel (110 octane minimum)
Maximum rpm
Reluctor Wheel

plus youll need about an aditional $2-$4K in lsx motor mounts flywheel bell housing headers,etc
now its 100% true that youll still need the the same parts with a old school big block swap, but the price of the parts will be lower on average. and you can run pump high test gas with the big block
going old school BBC I get 775 hp for about $14K thats $10,000 less
Bore & Stroke
Compression Ratio
Fuel Requirement
775 @ 6200 RPM
745 @ 4800 RPM
4.600 x 4.500
10.5 to 1
92 Octane

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solid fixture here in the forum
Staff member
Thanks grumpy. But as you said this is not a mega buck project squeezing out every last pony. On the contrary. It's about building an affordable, well-rounded 496

- I build the engine (fun!)
- Excellent idle
- Excellent street manners (not to come across as sexist but a lady should be able to drive it)
- Durability and reliability
- Reasonable 1/4 mile times

This became a 496. Fun to build. Fun to drive. Great idle. Won't break the bank.



solid fixture here in the forum
Staff member
In other words a bullet proof, regular pump gas, 12.5 sec, 9:1 compression 496 BBC. That starts, runs, drives and stops like a much newer Corvette.


The Grumpy Grease Monkey mechanical engineer.
Staff member
yeah! we can do that, and theres a ton of options if your checking account balance allows
Dart Big Block Chevy Big M Engine Block

  • Siamesed Extra-Thick Cylinder Walls: Resists cracking and improves ring seal (minimum .300'' thick with 4.625'' bore).
  • Scalloped Outer Water Jacket Walls: Improves coolant flow around the cylinder barrels to equalize temperatures.
  • Four-Bolt Main Bearing Caps: In steel or ductile iron have splayed outer bolts for extra strength.
  • Crankshaft Tunnel: Has clearance for a 4.500'' stroke crank with steel rods without grinding.
  • True ''Priority Main'' Oil System: Lubricates the main bearings before the lifters.
  • Oil Filter Pad: Drilled and tapped for an external oil pump.
  • Rear Four-Bolt Cap: Uses standard oil pump and two-piece seal - no adapter required!
  • Lifter Valley Head Stud Bosses: Prevent blown head gaskets between head bolts.
  • External Block Machining: Reduces weight without sacrificing strength.
  • Simplified Install : Fuel pump boss, clutch linkage mounts and side & front motor mounts simplfy installation on any chassis.
  • Dual Oil Pan Bolt Patterns: Fits standard and notched oil pans.
  • Bellhousing Flange and Rear Main Bearing: Reinforced with ribs to resist cracks.
  • Note: Does not include cam bearings, freeze plugs, or dowels
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