I bought a 79 C3 in November, an L82 automatic. There are a number of things to fix to make it roadworthy, but it does run and drive. The car has been wrapped since I bought it because I have no room in my garage/shop (because... junk storage) and the weather sucks, it's cold and rainy here, so I don't have a good read yet on the car details.

I have a loose assumption that the engine is pretty much stock. It might have been rebuilt sometime in the past decade. The intake and heads are stock, at least on the outside, and I'm assuming the cam is stock, but it might not be. The car feels pretty stock. (ppthh...) The q-jet is probably fine if I spend some quality time with it one weekend. I don't know anything about the stock alum. intake though. I'm guessing it's probably okay. Headers were added (yay) but they're wrapped so I have no clue what kind they are (yet). There's an aftermarket HEI on it that looks kinda beefy (as I remember).

Question is... After I get it all roadworthy (fix some rear-end stuff, shocks, exhaust system, etc.) I'm thinking of beefing up the engine (significantly) and I'm looking for some validation or advice. I want to replace the heads and cam to start. Retrofit a roller cam probably. My goal is to end up with a punchy street-only car. My track/strip days are long gone. But I'm up for a good burn-out anytime the opportunity comes up. So I'm aiming for lots of low/mid RPM power. Not planning on 6k+ rpm. Not planning a full-on 383 stroker build either. And I'm going a bit cheap on it, say, Promaxx rather than AFR. Just wondering which heads and cam specs you'd suggest for this application. Being a C3 with stock headlights, etc, it needs to provide plenty-o vaccum and that's got me a little concerned. What'dy'all suggest for heads/cam specs that will work. I have an idea but I'm no expert.

..Todd

 

Basically the L82 long block is a 71-72 Lt1 with a hydraulic camshaft, which is the L46 350-350 cam.
I would recommend change the heads to small chamber to increase compression and flow, have the carb rebuilt/tuned, and the distributor recurred with more initial timing.

 

May I suggest you have a look over in C3 tech. Same question with a 77 L82. Same answers so it'll save everyone a lot of typing if you have a look over there.

 

Thanks, but it's not the same question at all. Yes, I probably should have posted this in the C3 tech forum. Assume I've read and searched. I'm looking for cam and head spec advice for a specific configuration and goal, not looking for the usual well intentioned non-advice.
1. Use search (I did.)
2. Why bother, the car is worthless
3. Just toss in a xxx engine, since you'll never be happy with the power
4. If it were me, I'd do xxx instead.
5. Sell it and buy an xxx

..Todd

 

Call the cam companies for advice...too many variables

 

This really got my attention as well as I'm planning a project. So if the block is the same it would seem a hell of an idea to just shoot for a rebuild to 1970 LT-1 spec. Would it not be simple to just purchase the correct cam, heads, carb, manifold and, maybe exhaust if post 1974?
Why bother trying to customize from scratch when the blueprint for the best small block ever has already been written? Am I missing something? I would love to do this on a 74 or 75 convertible.

 

Your "Specific" needs are pretty much the same as 90 percent of us with street driven C3's.
I want power from 1,500-2,000 to 5,500. I want vacuum to power my headlights and HVAC.
Yup, same question, asked many times over.
Yes you have already reseached all over the net.
And although the 350 Chev is the most common engine on the planet, yours is somehow different. O.K.
.
Your aftermarket HEI looks "Beefy". Ya, O.K. but what ignition curve is in it? One for grandma's stationwagon? Or a true performance curve matched to your engine and the weight of your car?
What cam should I run? What compression ratio are you building with what heads and what transmission with what rear gears????.
A 400 H.P. (gross) engine is fairy easy to build from a L82 bottom end. But setting it up properly so it will work in your car is the Individual thing.
as per Vacuum to run your accessories. I run a L82 bottom end. At 10-1 compression. Honest compression. With a 268H flat tappet cam pulling 14.5 inches of vacuum at 800 RPM. No issues with headlights or HVAC.
your goals are actually modest. And yes, the answers in the now running post over in C3 tech are exactly the same answers you are looking for.

 

O.K. Todd. So, let's start with basic questions to you. Then we can recommend the best bang for the buck for a street driven car.
1. What rear gear?
2. What transmission? And if you have a automatic, what converter?
3. At what compression ratio are you about to build this engine? Quench?
Weight of your car? And who built, curved the distributor and set up the vacuum advance to what?

 

Well the pistons are probably. 025 in the hole, so you need to use an .015 steel shim head gasket to get a decent quench, if you get into the short block run 6.0 rods for a better rod ratio, 70cc combustion chambers for 9.5 cr, 170-180 cc heads for good velocity, and cam to match rpm range, cruise rpm, rear diff ratio, tc stall or rpm drop between gears if manual, match intake, carb, exhaust to above. Initial timing 14 to 16, total 36 to 38, all in by 3000 rpm. Easy peasy.

 

Or, .015 shim type head gaskets with more common 64cc chamber heads to give you 10-1 compression and approx. .040 quench. With the slightly higher compression still running on pump gasoline you will have a broader choice of cams that will work well.
but still, weight of car. Rear gear ratio, type of transmission, etc, etc.

 

Depends on the gas you have for 10-1, and how much overlap on the cam to keep the cylinder pressures in check for low rpm and cruising.

 

10-1 compression is about ideal in a small block chev engine in my opinion. Normal premium pump gasoline is more than adequate. Certainly is for me. Would be a radical cam in a street car to give you any issues.
yes I have a custom curved distributor, yes I have the correct vacuum advance can for my setup.
But never have I heard of anyone having fuel issues below 10.5-1. At least not if everything is setup correctly. We are not talking race engines here.

 

Since this car is running, do a few things to test it's health and performance. Find where a 1/4 mile is marked out, and run it to see what your MPH is and then compare to figures from back in the day. Do the compression checks, leak down if you have the capability, etc. plug reading, vacuum, timing, etc. etc. etc. See where you are, what you got, Then plan from that!

 

Drop the retro roller idea. The extra cost to go that way will cost you more than the stroker add, and no 350 roller cam will ever give you the torque the 383 stroker setup would.

If the bottom end comes out, I would stroke it. The cost difference to go stroker is cheap if you are already doing a rebuild.

If the bottom end is still good. you can use the cheap aluminum heads and a hydraulic flat tappet cam setup. I might suggest the Comp CL12-210-2. Its a 268H cam kit that is reliable and has been around forever. You can try the newer XE line but I would not. The faster ramps used in those designs have resulted in more cam failures.