Hello all I am brand new to this site as well as to owning a Corvette, my father gave me his 81’ with automatic, as he is fighting a loosing battle with cancer. The car is in disarray; it needs lots of stuff however I wanted to ask some questions about performance.

First off I want to install the performance Dual Exhaust Systems with Headers and MagnaFlow Mufflers offered by Corvette Central, A performer RPM intake and eddy 600 cfm carb, along with that an Edelbrock 7102 cam with the following specs.
Basic Operating RPM Range: 1,500-6,500
Intake Duration at 050 inch Lift: 234
Exhaust Duration at 050 inch Lift: 244
Duration at 050 inch Lift: 234 int./244 exh.
Advertised Intake Duration: 308
Advertised Exhaust Duration: 318
Advertised Duration: 308 int./318 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.488 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.510 in.
Valve Lift with Factory Rocker Arm Ratio: 0.488 int./0.510 exh. lift
Lobe Separation (degrees): 112

Along with that Summit has a nice HEI tune up kit with a new coil and ignition module
The smog pump will go, as the headers do not take the air tubes, I would also like to remove all the other smog “stuff” as I don’t need it here in Washington.

Questions........as I have always had late model cars, does this sound like an “ok” start for some moderate performance gains ?
Secondly, I know the carb, timing and Trans are controlled by the computer, so what rill happen with the fuel metering when I change to this aftermarket carb/intake setup ????

Thank you in advance for your suggestions and direction, I want this car to shine and pass it on to my son when the time is right......

 

The short answer is, if you replace either the carb or the distributor, you need to replace both. The trans control is limited to the lockup of the torque converter, which can be wired in to a switch.

Headers and exhaust are always a good first step and go a long way toward uncorking the smog strangled motors (assuming that you will be ditching the catalytic converters).

While I can not really comment on your specific choices, I'm going through the same process on my '81, and will be removing all of the computer controls along the way. Since I do not know how strong my bottom end is, I am going to swap in a new crate engine, most likely the GMPP 290HP base 4-bolt 350. It is a good value, will get me what I want performance-wise (to start). Unless you are totally confident that your bottom end is in good shape, I personally would not do a cam swap without rebuilding the engine, and with the low compression setup that came stock on the '81's, I'm not sure that the cylinder heads would be worth keeping either.

I would shop around, read up on what other people are doing here and do what fits your schedule and budget.

 

I think your cam is too hot. You won't be spinning the stock bottom end to 6,500 so why have a cam designed for that. That cam also won't work well with the stock heads.
For any real off-the-line performance gains, especially with a hotter cam, you will need a higher stall torque converter. You will get plenty of advice here.

 

Ok. thanks for that info....Hmmm all I am looking to do is get some extra HP.....the stock 190 is just a little low, the car has been sitting for a long time so I thought a new carb would be a good idea. So just the exhaust , the performer intake and a new carb and just run with the stock cam ??

 

You could benefit from a cam change, just something milder. You might call Comp and Crane etc. to see what they recommend.

 

Right any idea on expected HP with a *mild* cam and the above mods ?
Also I am still unsure about the disconnect from the ecu to the carb, I was going to keep the stock HEI and just hop it up........maybe I should just rebuild the Q-jet ?????

 

When you say "some extra HP" do you have any specific goals in mind. There has been nearly every permutation of modification done here by someone, so if you want to run a specific time in the 1/4 mile, or be as fast as some new car, that could give people an idea of what to recommend.

I have found that "some extra HP" is always going to be a goal, no matter if your car is bone stock or if you are John Force.

Down the road a ways, I plan on putting something like THIS in to my vette, but there is so much else that I want to do with it before I go and make it really fast.

 

Thanks Nate !! That indeed is a sweet combo. Well I am doing paint , old style rally wheels, and need a new interior and I mean EVERYTHING !
So looking for some performance gains without breaking the bank. This will be a daily driver and I was hoping for about 300HP........I had a 94 GT stang ( it was 260 HP ) and would like at least that out of my new bow tie.

 

The cheapest route to some decent power is to go find some used vortec heads off of a later model SBC (9?-98 truck engines, among others), get an intake that matches the vortec bolt pattern, open up your exhaust and get a decent cam that complements the heads, and you should be close to 300HP with your rebuilt quadrajet and a good tune up.

 

Ok, sonuds like I have a place to start !!

 

Vortec heads came on '96-'00 trucks with the VIN engine code "R."

 

Sweet. Now I will be a Head Hunter at the local bone yard

 

Vortec heads are a good choice. I have them on my engine. Don't forget that if you use them and a cam over .470 lift you will need to have the valve guide bosses milled down. If you're going to rebuild used heads, this is not a big deal. You should also install screw in studs at the same time.

 

OK, I'll throw in a little on that 81 your thinking about butchering.
First off you need a little education on what the CCC does:
It does indeed control converter lockup, thats a good thing.
The carb has 1 control and 1 sensor, the sensor is throttle position and the control is fuel air mix, thats it
The distributor timing is controlled by the CCC, set your base timing to 16* and you should be good.
That carb your about to replace with an 600CFM is already a 750 and a very good unit. With a little research you can set it up and not have to worry about it.
The intake you have should be an Edlebrock 2101, also a very good unit

Delete the smog stuff except the vapor canister and EGR. Neither of them rob any HP and do some good on emisions. The canister will keep the gas fumes out of your garage and the EGR only operates while at cruise, not on acceleration or slow speed, you shouldn't even know its there.
A lot of guys have put that exhaust system on that your talking about but its a not-quite-fit-all thing, your gonna have to mess with it a bit. You need to do this mod, its a Requirement for making any HP.

Heads is where your engine is getting choked down, Vortecs are good but require changing the intake, which will mean some other things so make sure the intake has the port for the temp sensor that tells the CCC what the engine is doing, it should since all the Vortec motors had a computer in them. I would go with AFR180 but they are pricy.
Take a look at the crane cam Summitt CRN114132. Its a middle of the road street cam for computer controlled engines.

you can do this in layers or all at once, since your new I would recommend doing it in layers and see what your results are at each stage. First should be exhaust, true duals no cat and be sure and put the O2 sensor close to the collector as possible.
Remove the AIR pump at the same time.

You can do the heads and cam after that, you will need new lifters, timing chain kit, head gasket kit, oil pan gasket etc..

That ccc carb and distributor are capable os supporting a 350 hp engine or more

Good Luck, welcome to the Forum, congrats on the car and sorry to hear about your dad.

 

I didn't read everything here carefully, but I'm surprised that nobody has mentioned to you that you are wasting money replacing some things that will give you no performance gains. Most notably:

The Manifold: The stock manifold is good. It also works well with the stock hood and stock cold air intake. Putting in an rpm manifold on will require a drop base air filter. This is a common mistake people make with these cars. The stock set up will out perform an rpm manifold with an open element sucking thin hot air from under the hood. If you wonder what I mean, put your face into a hot engine compartment and try to breath. There should not be any fumes, but you will still feel like you are choking. It is because the hot air under the hood has so little oxygen. Combustion requires oxygen! The stock set up gives you plenty of it.

The carburetor: The 750 cfm E4ME is the most highly advanced carb ever made. Properly set up (with the stock computer), it will keep your A/F ratio at 14.7:1 (ideal efficiency) for normal cruising, and will flow all the fuel the car will ever take at the ideal performance ratio at WOT (wide open throttle).

The distributor: If you replace the carb, you will have to replace the distributor. The stock distributor can easily be set to give you a performance timing curve that will always be there, and if you should happen to get any potentially engine destroying detonation, the computer will sense it and back your timing off 2 degrees, saving your engine. Why in the world would you throw away such a system?

Once the computer is gone, you will have to set the transmission lock up to work without it.

If you do all of the above mentioned mods, you will have spent ALOT and the car will be slower than when you started!

Replacing the exhaust and cam are good things to do. The pre-fabed systems are expensive though. My whole ceramic headers/ 2.5" dual system cost me less than $500 installed. Add a Comp XE 262 H cam and these two mods alone should almost double your HP.

Better yet, take the money you were going to waste on useless mods and invest it in a roller cam set up (Comp XR 264 HR).

If you are going through the whole engine now, good heads (Dart, AFR) and pistons (Flat Hypertuetics) should get you in the upper 300hp range.

God bless, Sensei

P.S. Vortec heads are good, but they do require a new manifold and you will need to have them worked on if you get them from the bone yard. For that money, you can get a good set of new Dart Iron Eagles that just bolt on.

 

Ok sweet...this is the reason I joined the forum, you guys have given me allot to think about. I had NO idea that the manifold and carb were so good. I will keep the stock distributor and carb and manifold and the ccc.

I will do the cam and heads later and the exhaust and a k&n filter right away.
Thank you for the direction and for helping me put my cash into the RIGHT parts !!

You guys are great !!

 

Do the exhaust first, you will notice a HUGE difference. True duals with no cats is ideal. When you say the car is in "disarray" then that tells me I would do a complete and thorough service of the car (if you haven't already), new plugs, wires, change the oil/fluid in every component (transmission, rear end, engine, radiator), and lube. Inspect everything including the brakes, suspension, rear end, u-joints (among other things), to see if there is something (other than performance gains) that needs to be taken care of ASAP. Get someone that really understands timing and check that also, there are usually a few ponies to gain there by adjusting it a little (without causing any pinging). A good service of the carb is probably in order also, but I agree with the other posts that there really is no need to change the carb, intake or computer, nor would I tear into the engine unnecessarily. I love the sound of when the huge secondaries kick in on a quadrajet. A mild cam is all I would really do other than the exhaust and major servicing to start. After all of this, then you can take it to the track and see what it is really doing before getting too crazy. How does the engine run now?

 

The car has sat for 4 years and the battery is dead, it it in Texas and I am in Washington, so I have not been able to start it, I found the carb all rebuilt for $218.00 http://www.guaranteedcarbs.com/cgi-b...8&keywords=all

Looks like a good deal

As far as the breaks go I have a complete set from Ecklers new rotors, stainless breaklines and calipers http://www.ecklers.com/product.asp?p...1&dept_id=1034 They have O-ring seals....I guess my dad said they were the *good* ones

I also have new weather seals for the enitre car.
So belts hoses all fluids, and the above engine mods to start, along with the new interior kit and a few coats of 2007 Atomic Orange paint

 

That carb "Looks" real pretty and it mught even run fine if your lucky. I would still go thru it to make sure the builder hasn't thrown in a bunch of crap, it happens more than you would think.
Make sure the jets and needles are matched, the needle springs are good, needles not dammaged and very importantly that the plunger and TPS adjustments are EXACTLY on the money. Also look at the fuel filter inlet, they like to goober those up. So, if ya have to do all that to make sure your not getting ripped off, you might as well just rebuild the one you have for $25.
A1Sensei knows his business, I learned a lot fro him

 

I have been into one Q-jet before and a few Hollys....so this one should be no different.