Quote:
Originally posted by gonadman
I've got an 86 corvette with a 350 TPI. I've opened up the exhaust, and am getting an aftermarket cool air induction system. I plan to add a 160 powerstat and a performance chip.
To get maximun HP for the money, what would you think the best next step is, manifold/headers or camshaft? Is this something I can do in my garage with basic tools?
Thanks for your great offer of answering our questions!
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I'd recommend first and foremost that you get a better intake manifold, a freer flowing one. This however, will be useless without the headers & exhaust to go with it.
It's all well and good for more air to be able to fly into the engine, but that won't happen unless more air can flow out as well. You want to increase the flow throughout an engine in all areas, leaving no bottlenecks.
Basically, get the aftermarket intake manifold (I can't recommend any brands for your car sorry, do some searching, I have an Edelbrock Performer on mine), and get 4 into 1 extractors at the same time.
You should be able to fit your new intake manifold by yourself at home... I'd recommend buying new gaskets for it to seal it properly though, as air leaking in past the manifold can prevent the engine from running fully in tune.
The extractors/headers may not bolt directly onto your current exhaust piping, so that's why you may need an exhaust specialist to fit that for you. If you do want to fit it yourself, you'll probably need to undo an engine mount on one side, jack the engine up from underneath, then feed the extractors up from under the car and bolt them to the head... for both sides of course. That's how my extractors were fitted.
When these are both fitted, you'll need to retune your fuel system... or possibly even upgrade the injectors & fuel pump to ensure the engine is getting the right fuel to air ratio mixture. When my new full exhaust system was first fitted to my V8, I already had an aftermarket intake manifold & carburettor, however it was out of tune because it wasn't dumping enough petrol in to match the now higher airflow. (I've since tuned it
.)
After those mods, I'd recommend upgrading your ignition system to have electronic spark timing, bigger coil, better quality spark plugs & bigger leads. 8mm to 10mm leads should be fine for your application, my engine has 8's. You'll be amazed at the power increase just by giving the engine better spark. You can get these MSD coils which spark several times during the combustion cycle, ensuring complete burning of the fuel.
After that is where you'd want to get your performance cam, as this is a slightly more intense mod which will cost a bit more money to buy & install. Shop around and make sure you learn about cam specs, what valve lift, duration, & the timing figures all mean. You shouldn't just get any old performance cam, you want one to match the characteristics of your engine & take advantage of the increase air flow.
With all the above mods, your motor should be able to produce anywhere between 300 to 450 horsepower, largely depending on what kind of cam you get & how high you can rev the motor.