1977 Impala Modifications

Asked by Jul 04, 2017 at 01:22 AM about the 1977 Chevrolet Impala

Question type: Car Customization

I was fortunate enough to find a 1977 Impala 4 door 350
engine with 148967 miles. Now that I have this car I was
wondering what modifications I can make to the engine to
improve the performannce and still meet California smog
standards. I dont really want to swap the engine, I bought
the car from Southern California and drove it up to Northern
California surprisingly we made it without any issues. Any
suggestions that will comply to CARB standards and still
give some good power?

6 Answers


Depending on your budget, and what you want from your car in regards to performance. Edelbrock makes a series of performance kits that are CARB certified. For maximum gains. There is a Complete kit including Carburetor Intake manifold cylinder heads cam lifters and springs. Add a set of CARB compliant headers and a good exhaust system and you will have something nice and legal. There are also kits available with fewer components.


My go to answer for all questions similar to yours, though you mentioned you don't want this: LS swap. You will be blown away. Will meet the Nazi "California codes" and get the same gas mileage with a 500 HP LS motor as your neighbor's economic Maxima.


Any engine swap in Kalifornia must be smog legal and pass inspection by a state smog referee. Read this before proceeding ---- --- https://www.bar.ca.gov/Industry/Engine_Change_Guidelines.html


An engine swap to modern fuel injected engines is actually welcome in California, You will have to pass an inspsection once the car is completed. But if the swap is done right it's a snap. It's actually easier to pass the smog test after this is done. But modifying your original engine is perfectly legal and acceptable if you use CARB certified parts and don't tamper with any original smog equipment. You must keep the CARB compliance paperwork that is supplied with the parts. They also come with CARB stickers for placement under the hood near the OE pollution control sticker. The only smog equipment that should have been on your southern California car is. A catalytic converter, an air pump, and a sealed vapor canister. California is the home of the hotrod! and tougher emission laws have not changed that.

1 people found this helpful.

Capn_Steve can you explain the engine swap process. How will a car pass smog after the swap? What parts must I use to successfully swap the engine? Any more tips or suggestions? Can I possibly swap an LS2 engine and still pass smog? If so how would that work? Thanks


the easiest way is to find a donor vehicle. Chevy trucks came with a 5.3 liter 300 hp ls engine and a 4L60E overdrive trans.you will need a two wheel drive truck though. These are relatively cheap wrecked. You will need the engine, transmission all of the engine wiring and engine management computer.you will need to have an exhaust system made. But if you use california certified obd 2 cats you will still be legal.You will also need a fuel system that is compatible with fuel injection. That consists of a high pressure electric fuel pump. and a return line setup. You will also have to connect the vapor canister from the donor vehicle to stay smog compliant. You will need some other odds and ends. Like a cross member for the trans, a driveshaft, and a few other things. As far as making sure you are legal, you can contact the Bureau of Automotive Repair (BAR) To insure that all guidelines are followed, and requirements are met. Then once the work is done Call them back to schedule an appointment to have a referee certify the vehicle smog compliant. Then you get to take the anual smog test like any new car does.

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