gbarrett

My wife has a 78 Vette, very low miles. She keeps asking why it doesn't have more power. I've tried to explain the Carter Administration and all of the fun of the pollution control of the 70's but it's not enough. She wants to be able to smoke the tires.
What's the best way to proceed? I'm not made of money and the car is bone-stock and I'd like to keep it reasonably close.

Thanks for the help!

Greg

CanadaGrant

My wife has a 78 S/A and it is pretty easy to get some horsepower without breaking the bank. If you can do the work yourself, heads and cam will come close to what she wants while sticking with the original motor.

Jim78SA

Follow Lars' article in the stickies on HEI ignition timing. It is good for another 10 HP or so. If it is a L48, you can get a relatively cheap aluminum intake. You could also purchase true dual exhaust and a set of headers. If you have some money you could get a set of heads, cam, and torque converter.

badrad

Start with a performance tune up. The factory settings leave a lot of power on the table. Beyond that headers and intake would be next for me.

bluedawg

To smoke the tires either a gear change or a manual tranny conversion would give you low end grunt. You didn't say what your budget was.

rcread

Get some 165 tires.

c3_dk

I would like to marry your wife, is that possible ??? ;-)

Street Rat

Higher numerical rear end gears. Everything stays stock up front.

scottyp99

Purchase this kit:

http://www.summitracing.com/parts/mr...make/chevrolet

Send Lars Grimsrud an e-mail at v8fastcars@msn.com and ask him to send you copies of his papers on How to set timing, and vacuum advance units. Follow the instructions.

What you will be doing is known as re-curving the distributor. It'll be the best 9 bucks you ever spent. Next, headers and a 2 1/2" dual exhaust. Tell your wife she has to pay her own speeding tickets.

Scott

Easy Mike

Automotive emssions laws began before the Carter administration. If it's your wife's car, why not let her decide what she wants to do with it?

Is it time for a tune up?

terry82

how much do you have to spend?most start with exhaust .gears are great .how much do you want to do .how much do you have to send out.

garygnu

header,dart iron heads ,comp 268 extreme cam.a elderbrock performer intake with the stock carb .a good Hei distributor .it can be done for $1000 if you do the work your self .

MidShark

REELAV8R

One of the things holding you back is the stock exhaust system.
I have a 77 vette and would guess it's very similar or identical to your 78 in the engine and exhaust department.

The stock exhaust has a restrictive catalytic converter installed. Remove that for better exhaust breathing. Are emmision laws a problem where you live?
If not then feel free to mod the exhaust how you like.
I would recommend headers and 2 1/2 inch dual exhaust system with free flowing mufflers. Any decent exhaust shop can handle the job. Get a quote first though to see if it's in your budget.

The stock Q-jet can be modified with great success and this will make a big difference in the responsiveness of the engine and over all running when hot or cold.
Get this book and follow it.

Or send it to Lars and let him rebuild it for you if rebuilding it yourself is not in the cards.

And like the other guys have suggested get the timing re curved using Lars' papers. It makes a big difference in off the line performance and the engine will run cooler too.

These are the cheapest options. Heads and cam becomes much more involved.

One more item is removing the stock cooling fan system and installing electric fans. This can free up as much as 15 HP from the engine assuming the electric fans will pull about 3 hp due to additional load on the alternator. This is starting to get into some money though unless you're pretty handy and can rig up some used parts on your own.

7T1vette

There are a number of things that can prevent the Q-Jet secondaries from opening or opening fully. That is the place to start.

1. Verify that the secondary lockout lever is NOT preventing the secondaries from opening when the choke has warmed enough to release it. If this isn't working right, the engine will never see the carb secondaries opening at all.
2. Once #1 is operating correctly, have wife put accelerator pedal to the floor (with engine OFF) while you look down the carb venturi (you will have to manually hold the upper air flap open). With accel pedal fully depressed, the lower throttle plates [butterflies] should be standing exactly vertical. If they are not opening fully, adjust throttle cable/linkage/accel pedal as required to obtain vertical position. If the throttle plates are going past vertical, adjust the carb linkage to set them in proper position.

If/when the carb is working properly at WOT and you still don't have 'adequate' power [for a stock, late-70's C3], you should verify that the mechanical advance mechanism in the distributor is working properly....then optimize it for engine "performance" per Lars paper on setting up the distributor. This change will make a considerable impact on engine performance {over how the stock distributor is set up}.

DO NOT throw money at new performance parts before you verify that your present carb and distributor are giving you all that they have.

johnt365

... and that is my exact motor pretty much. That plus a 200-4R transmission and a 2400 converter tied to a 3.55 rear gear = FUN.




(when I read that I felt so transparent and uninspired. with all the engine combos and possibilities out there... man. it is a fun car now though. )

Priya

That's some good advice right there - before you do anything veryify that the motor is running as it should be. Since I got my 79 L82 I thought its running rougher than it should be for what it is. Replaced plugs, plug wires, distributor cap and rotor and its slightly better. Told the hubby I wanted to check the timing and asked him to bring home his timing light. He had a bit of a "Why bother, timing doesn't vary with electronic ignition, there's no reason it should be out" attitude. He brought the timing light home anyway and I find the timing is 10 degrees retarded from the recommended setting. Haven't been able to adjust it yet, though because the darn distributor hold down bolt is so tight hubby's afraid it'll break if he pushes on it any harder. Been soaking it with WD40 for a few days now...

augiedoggy

I have a comp 268 cam and an edelbrock performer intake for sale cheap!
I managed to pick up a set of dart iron eagle heads complete with roller rockers for $300. on craigslist. I would say heads and exhaust would be the best bang for your buck...

Gears are not usually the answer since they are a tradeoff .... it will feel like your driving a tractor on the highway and the rpms will be very high.

gbarrett

Wow!! Thanks guys!! A lot of great options. I'll start with timing and go from there. The car has less than 28,000 on it. The wife wants the car to sound more aggressive so exhaust will definitely be replaced. She's envious of the way my 1974 Vette sounds. She doesn't really know much about the mechanics of the car, she just wants more power and meaner sound.

Thanks again!

johnt365

Hi Greg,

Fun post you have going here. Here is a link to some rear wheel dyno data from my car that may interest you.

http://forums.corvetteforum.com/c3-t...mp-xe268h.html

I calculated the dynamic compression ratio for that dyno pull at 7.3:1 Which is low but it was still a fun car.

Did you say if you have a standard or auto and what your rear gear ratio is?

Its a lot of work, but converting to one of the overdrive transmissions can be a game changer. Especially if you drop to a lower rear too. It gives you the best of both worlds, better off the line take off and lower rpm cruising. I would not rule it out.

Cheers,
John