No way to do that without pulling off a head and measuring them.
1.94 intake and 1.50 exhaust
Probably 1.72 intake and 1.50 exhaust, but also could be 1.94 intake and 1.50 exhaust.
305s had 1.72" intakes with 1.50" exhaust valves. Depending on the 350, it could be the same, or have either 1.94" intake and 1.50" exhaust, or 2.02" intake with 1.60" exhaust.
Depends on the heads. The size is different for the exhaust valve and the intake valve, and different engines have different size valves. The valves are mechanical devices in the engine heads that open and close. The intake valve opens to let the air/gas mixture into the combustion chamber,. Both valves close the combustion chamber during the compression stroke, and the exhaust valve opens to let the burnt gas out during the exhaust stroke.
Depends on engine size. Typically two valves per cylinder. One intake and one exhaust. Some higher performance applications can have four valves per cylinder.
like what size for intake and what size for outlet
Intake valves are are almost always larger than exhaust valves . The exception may be in a low performance small engine where sometimes both the intake and exhaust valves are the same size.The intake phase of the 4 stroke cycle relies on engine vacuum produced during the piston down stroke to draw the fuel / air mixture into the cylinder.Vacuum (as opposed to pressure) is a relatively weak force; therefore a larger opening (larger intake valve size) must be provided in order that sufficient quantities of fuel and air enter the cylinder - for the engine to run.Removing the exhaust gasses is a much easier task - due to the pressure created by the upstroke of the piston.Because the pressure created by the piston is a much stronger force (than the vacuum the piston created during the intake stroke), the exhaust gasses can escape (they are actually pushed out) through a much smaller opening, past the exhaust valve.The intake valve is bigger.
Please clarify your question. Which engine are you asking about, the 2.5L 4 cylinder or the 2.8L V6. Then are you asking about the size of the exhaust pipe or the size of the exhaust valves or some other exhaust feature?
The valves are probably not changing size from the heat. It's more likely something is causing the cam to wear out, such as a lifters that are not revolving, the nuts are backing off, or your valve adjustment procedure is flawed.
It affects how the engine breathes. The better it breathes, the better the performance.
I have the same heads and from the info I found they 76cc heads with 1.72 intake valves
You need to know the engine size and (in some cases) manual or auto transmission combination. There is usually a different horsepower rating for auto versus standard engine size/tranny combo, hence a different lift/duration (height/time not only the intake but the exhaust valves are open). You can check any reputable parts store that sells trw parts (for example) and find the recommendation for stock as well as performance replacement cam kits.