Looking to find out what are some basic performance upgrades on a 89 305 tpi irocz.

 

Cam, roller rockers, heads, intake system, throttle body air foil, exhaust, headers, Just about anything that is upgradeable from a 350. Take a look at a performance catalog from either Summit Racing or Jegs. They have a bunch of things in there.

 

what upgrades would be the easiest and yield the most performance boost

 

I personally, think that headers and a free flowing exhaust system are one of the best bang-for-buck upgrades. Even if it dosent make it a lot faster, it will FEEL and sound faster. Also, you can never go wrong with a K&N air filter. Wanna spend more and get even more power? Go with cam and heads.

 

Priorities;

1) exhaust
2) sub frame connectors
3) rear end gears
4) camshaft/intake manifold/heads. <- These should be done at the same time to avoid re-tearing down the engine, and to get maximum results.

 

is a new intake manifold just an easy swap or is it a time consuming process. should runners go along with this. how much should i be looking to spend and how much extra horses am i looking at

 

If all you do is an intake swap you won't notice a gain. There's much bigger gains to be had in other places, leave the intake until you do heads/cam

 

where are the other gains???

 

as Sonix said, exhaust, rear gears, cam+intake+heads.
Other than that there's always a power adder (supercharger, nitrous) though you wouldn't be able to get much out of those on stock internals, other than that you're pretty much down to weight reduction, and expensive pieces that only free up a couple horses (underdrive pulleys, electric water pump, etc).

 

what are rear end gears?

 

The gears in the differential. They come in different ratios, in the format (number of revolutions on input) : (1 revolution output)
example 3.23:1 takes 3.23 revolutions of the driveshaft to turn the wheels once.
Lower numbers will give lower RPMs at any given speed, and are generally better for fuel economy, higher numbers make the car accelerate quicker but the engine turns faster so economy goes out the window.

 

what are good rear end gears to get?