I keep reading about everybody modifying their cars using heads, cams, and intakes. First of all I don't have a clue what they are talking about or what they do. Can someone explain what they are and what they do to improve the performance of their cars. Is this the way to go to make my car faster. Love my car but it needs to go faster. Not afraid to spend the money to do this. Are heads the same as headers. If not what are headers and why do they make such a drastic improvement in a cars performance. I love my 87 Vette but I just don't know a lot about engines. Don't want to upgrade to a newer car, because I graduated in the 80's and that is the car generation I love. Thanks for all your help.

 

First of all, keep in mind that your car by todays standards is old technology. Advances have been made to heads to make them flow better (getting fuel in and exhaust out). Also keep in mind that when our cars were built they were and are a compromise of materials/labor and costs.

To get more power, you have to get the air/fuel into the engine better and the exhaust out better than the original setup. My 1985 is known to have a very restrictive exhaust and the iron heads were good at the time it was built, but there are much better products on the market today.

First if you concentrate on getting the air/fuel into the engine. This is accomplished with better/bigger plenums, runners and intakes. These can still be improved by gasket matching and grinding away restrictions. Gasket matching is where you grind away the material on an opening so it matches the holes in the gaskets coming and going. The lobes on the cam lift the valves to allow air/fuel into the head and exhaust out. Changing from the stock cam to a higher lift and longer duration (valve stays open longer) allows more air/fuel in and exhaust out. The next best thing is the heads. A good set of aluminum heads with bigger valves (remember better in and out), tested and changed designs to the runners to the valves and chambers themselves add to this in and out logic. Now you have a good set of heads that flow much better than your stock heads. Now lets get this spent fuel/exhaust out. Headers have larger diameter tubes than the standard exhaust manifolds. Long tube headers have more area for the exhaust to flow out and good design to a quality header help pull the exhaust from the heads. Larger diameter exhaust pipes again add to the ability to move the spent fuel out. High flow cats and better mufflers again eliminate restrictions. The important think to keep in mind that these items are additive (they all add to more HO and Torque). But just doing one area will not give you as much power and addressing all areas. Adding better intakes but not heads gives you the hour glass effect. Adding the heads after the intake just moves the hour glass restriction further back..the exhaust. Address all these areas with a good logical plan with tried and true good parts and you will have a great running engine that will product horsepower. But also keep in mind that additional HP and torque lead to additional areas that have to be addressed.....transmissions, drivelines. rear ends and gears.

Now a real world application...by 1985 was stock at 230 HP at the crank. I changed intakes, runners and plenum to the Superram (much better flow and more area). Next the old iron heads were replace with AFR 180 aluminum heads (bigger valves and Much better flow). Added 1.5 & 1.6 roller rockers. This lifts the valves on the cam higher to allow more air in and exhaust out. Front "Y" pipe changed from 2-1/4" to 2-1/2". For the track I pulled the high flow cat and used a straight thru pipe. Now the base block was still the same....same original pistons and cam. The old setup was running 14.6 at the track (remember the 230 HP). After the changes.....13.6 thru the 1/4 mile and still pulling hard. Dyno tested this setup at 345 HP at the crank and about 430 pounds of torque. That is a good improvement and I was getting 27+ MPG on the freeway for 1600 mile trips with this setup.

I expect more from the current ZZ4 application, but this is untested at the track and dyno at this point.

Hope that helps.

 

Thanks so much for the info. Is this a do it yourself deal or do I have to have true mechanics do this kind of work. I'm sure I do. How much did all that work cost you? Could you recommend a set up for my 87. Parts and where to get them and possibly anyone out there know of a place in Denver to do this kind of work? One more question is what is a ZZ4 application? Or would it be easier to go with a supercharger. Thanks for any help I can get.

 

.. Where to start?

First, before you start throwing money in your car, I suggest you learn about motors and how they work. John did a wonder job explaining the mechanics of a motor, but this doesn't show you what each thing looks like and what you should get for your own application.

The best thing for you to do right now, would be a simple cat-back upgrade. Search for a 85-91 cat-back on either summitracing.com, jegs.com, or an aftermarket exhaust website like Corsa, Borla, Flowmaster or Magnaflow. It will make your car sound better than stock, and offer a moderate performance increase.

 

Sounds like you could benefit from some reading. There are good books by David Vizard and David Emanuel John on engines & power trains and by Baechtel on TPI. If you intend to turn wrenches on your C4 the "Shop Manual" by HELM is indespensable.

On my site there is an example of a buildup on a late L98 along with power and performance gains. The result was around 375chp and a very solid high performance street car.

 

I would start here. All to many people jump into reading and thinking they know what they are doing without truly understanding the basics. Pretty soon on down the line they are making all kinds of mistakes because of the gaps in their early knowledge.

http://auto.howstuffworks.com/engine1.htm

 

Thanks again for all your help guys. This is an awesome web site for people like me who don't understand the true mechanics of their car. Once again the Forum comes through. Any more suggestions. I'm all