Hi there am new to this forum and was wondering if you guy can help me out with some info. Ok my car is an 85 z28 w/lg4,I just bought the car before the winter here in Canada. Ok the guy I bought it from did some work to it but am not sure what ( I have limited knowledge of cars). From what I can see he has aGma dress up kit (well valve covers and open filter) and edelbrock headers and I think full exhaust from front to back about 2.5" with one magnaflow muffle with dual outlets. I think he took out the emission stuff as it doesn't need an emission test here anymore. The engine compartment is fairly clean like not full of hoses every where(that is why I think some of the emission stuff is gone).

My questions are.

1. How do I tell is the emissions stuff is gone?
2. The distributor has a vaccum line pluged and is an accel with accel wires is this good?
3. Is there a way to tell if he changed the heads?
4. I drove a stock z w 305 and the cars are night and day would theses few mods I know about make that big a difference?
5. What gains would I see from changing from an open paper filter to a k&n?
6. Finally what other simple mods can I do to make it a bit quicker?

Thanks for reading my long post but I would much rather squeeze as much as I can into one post. Also I want to stick with the 305 for now cause I don't have the knowledge or skill to swap out to a 350 nor do I have the money to pay someone to do it. I do on th othere hand could probably manage to do some fairly simple mods like change to electric fan or maybe swap heads.

Again thanks

 

Welcome Aboard!

I'll try to tackle the questions one at a time.

If the car is an export (Canada-specific) model, it would be identified as such on the VECI label under the hood. That being the case, it should have had an EGR valve, and EVAP cainister, an EFE valve at the end of the RH exhaust mainfold, and a THERMAC valve in the stock air cleaner.

The vacuum line to the distributor should be connected for both improved fuel economy and peak performance. The line is normally disconnected only when setting the base ignition timing, and someone may have forgotten to reconnect it. If your distributor has TWO vacuum lines, one is for spark advance, and one is for spark retard on cold startup or deceleration. You would need the appropriate Temperature Vacuum Switch installed to activate that spark retard unit properly.

As for the wires, Accel wires are simply a yellow version of the factory silicone jacketed 8mm resistor wires, and are almost as good as factory wires.

The heads can be identified by removing a rocker cover and reading the seven- or eight-digit casting number between the rocker studs.

"Night and day" meaning which one seems to drive better? You lost me on that one.

The main advantage to a K&N or other polyester element type filter is that they tend to flow air at a fairly consistent rate even when they start to get dirty. A new, stock, pleated paper element should flow just as well, although flow will reduce faster as it gets dirty compared to a polyester element.

The bigger problem is that the element is OPEN, allowing the engine to ingest heated underhood air. There was a reason the factory installed an air cleaner with a snorkel routed to the front of the vehicle and not drawing hot air from the engine compartment. In your case, the headers are likely making the situation even worse by heating the engine compartment even more.

You might be better off finding a stock air cleaner from a salvage yard and installing all the necessary ductwork to get colder intake air to the engine. If you are lucky enough to find the L69 design air cleaner (dual snorkel), grab it up, even if you don't intend to use it. They are rarer, and in high demand. It's also fairly easy to use parts from two "regular" stock air cleaners to fabricate a dual snorkel type, so you might be looking for two of them, along with two sets of intake ducts.

"Simple" is a relative term. To some, changing a camshaft is "simple" work and can make a significant difference. That may have already been done. It would probably help to know what intake and carburetor are installed. The headers and exhaust work are a good step, even if the 2½" pipe may not have been the best choice.

 

Thanks.

As for question 2 I know the vacuum line on the passenger side is plugged It kinda looks like a valve of some sort about 2 1/2 inches in dia. kinda pointing towards the front passenger side corner of the car.

As for question 4 My car seemed faster then the stock z but it could also be one of those sounds better means feels better.

So question 5 I guess your aswer is to put back on the stock cleaner and run a duct so it gets colder air.

Question six to me I would rather not get directly into the engine like pistons, cam. I would feel comfortable with changing heads, intake, carb( but I know the q-jet is good)