enzo56

Good Afternoon :

I just recently purchased a 1985 Corvette C4 from a very sick friend of mine. It is a beautiful car but as the hot rodder that I am, I want to increase its horsepower. Can anyone help me without taking the engine out and boring and stoking it. Also I am looking at putting headers on it as well but I noticed that the current exhaust has a tube that runs, both sides, from the exhaust to what looks like the EGR valve. Do I need to drill and tap the same configuration on the new headers?

Thank You

84wuzmy1st

You can buy headers that specifically already have this A.I.R connections.

MrWillys

The EGR sits atop the manifold base under the plenum is gold in color and about 3 1/2" in diameter. It helps you get better mileage, and only operates in high vacuum part throttle situations.
What you describe is AIR (air injection reactor). It pumps air (78% nitrogen, 21% oxygen, and 1% inert gases) into the exhaust to burn any unburnt gases. Depend on your states laws, you may, or may not remove this system.

John A. Marker

Welcome to the Forum. Your referring to the air tubes that go into the exhaust manifold.

PM Sent

aklim

Headers, intake manifold and a dyno tune to begin. What is your location? Someone might be able to suggest a facility

ghoastrider1

headers and true dual exhaust is a good start. Next is the top end..MAF, runners and manifold. Lots of guys are dumping the 16 inch wheels in favor of the 17 inch ( 9.5 wide)wheels. Should put you in the 13s in the 1/4

aklim

I'm not sure true duals are a good idea unless you either put a H or an X pipe.

Why mess with the MAF? I wouldn't fool around with the MAF if it were my car. IIRC, it can support much more than what the 350 will produce for the most part.

DinoBob

That is not quite correct. While there are states that do not check emissions on cars that old, it is a Federal crime to remove or disable any factory-installed emissions control system.

70ZZ3 96LT4

How much horsepower is he going to obtain with headers? A 1985 Corvette was the first American car to post a top speed of 150 MPH. The 1985 Corvette does not put out much HP above above 4,500 RPM. At what RPM do headers help?

enzo56

Thank you so much for your reply. I live in Ontario, Canada and here our emmission, testing, is only for vehicles 20 years or younger. They are strict though that if it came with cats then they will look underneath to see if carts are there only. That is why I am looking for flow through. May I ask if I can remove the AIR connections and not affect the performance of the car?

Thank You

enzo56

I live in Hamilton, Ontario Canada.

Thank You

enzo56

May I ask what an MAF is?

Thanks

ghoastrider1

MAF is "Mass air Flow", Sensor. Long tube headers kick the bottom end tourque and hp up.

aklim

An excellent shop I know of is in the Minneapolis area of Minnesota.

gerardvg

When my 85 was standard she did a 14.4 quarter mile, next week with headers it went down to 13.6. Later with cold air intake and adjustable fuel pressure regulator and timing adjustment i got it down to 13.3 quarters. a few years later i fitted a blower.

Headers just gave more power mid range to top end, totally changed the car. Food for thought